Coffee Roasters

Abstract

A coffee bean roaster (1) is disclosed. The coffee bean roaster (1) comprises a roasting unit (11), a sensor arrangement and a control unit (13). The roasting unit (11) has a drum (111) having a transparent and removable front wall (1112). The roasting unit (11) further has a hot air supply device (114) and a rear wall heater (116) to heat the rear wall (11111) of the drum (111). The sensor arrangement comprises a roasted bean temperature sensor (12a). The control unit (13) is configured to receive a control input signal as a function of time, wherein the control input signal comprises a roasted bean temperature signal and a roasted bean color signal, and is further configured to automatically generate a control output signal as a function of time in dependence on the control input signal, thereby controlling the operation of the drum heater (116) and the drum rotor drive (113) to roast the coffee beans inside the drum (111) according to a predetermined selected roasting profile, wherein the selected roasting profile comprises a desired roasted bean temperature as a function of time, a target roasted bean temperature and a target roasted bean color, wherein the control unit (13) is configured to determine whether a roasting end condition is met, wherein the roasting end condition comprises that the coffee beans inside the drum (111) have the target roasted bean temperature.

Description

Technical Field

[0001] The present invention relates to the field of coffee roasters and roasting of coffee beans. Background Art

[0002] It is known that roasting of coffee beans is a highly complex process which depends on a number of parameters and influencing factors and which generally requires considerable skills and experience. For roasting coffee beans, coffee roasters in the form of large industrial plants are known and are mainly used. In addition, smaller coffee roasters can be used to roast small quantities of coffee beans, for example up to 1 kg or several kilograms, and are used, for example, in shops and in some private households. However, especially those smaller coffee roasters still tend to require a great deal of skill from the user (which in many cases is not present) and further require a great deal of attention from the user or operator to provide satisfactory results.

[0003] In addition, coffee roasters typically produce hot and odorous exhaust gases, which require use in a well-ventilated environment and / or require costly and expensive exhaust gas treatment. In addition, the cooling of the coffee beans after roasting is often unsatisfactory, resulting in suboptimal roasting results.

[0004] The general aim is to improve the prior art regarding coffee roasting, in particular by means of small coffee roasters suitable for use in, for example, shops, cafeterias etc., while producing high quality roasted coffee beans.

[0005] Advantageously, some or more of the aforementioned problems and disadvantages are at least partially overcome. Additional specific advantages present in various embodiments are discussed in their respective contexts. Summary of the invention

[0006] In one aspect, the general object is achieved by a coffee roaster for performing a coffee bean roasting process. The expression "coffee bean roasting process" may include, in addition to the roasting process itself, further processes or methods, in particular a post-treatment of cooling the coffee beans after the roasting process itself, in particular by a cooling unit, and / or a waste gas treatment and removal of dregs, in particular by a waste gas treatment unit, as well as filling with green coffee beans and removing roasted coffee beans. The expression "roasting process itself" directly refers to roasting the coffee beans inside the drum, as further explained below.

[0007] It is noted that in this document, the cooling unit as well as the exhaust gas treatment unit are described in the context of a specific embodiment and overall design of a coffee roaster, as further described below. However, they can also be used in the context of a coffee roaster of a different design. A separate lawsuit for the corresponding subject matter is expressly reserved.

[0008] In a further aspect, the general object is achieved by a coffee roasting system. The coffee roasting system includes one or more coffee roasters designed to be operatively coupled to a remote computer system.

[0009] In a further aspect, the general object is achieved by a method of roasting coffee beans and / or brewing coffee, wherein the method comprises using a coffee roaster and / or a coffee roasting system according to an embodiment of the present disclosure.

[0010] A coffee roaster according to the present disclosure may include a roasting unit. The roasting unit may include a drum, wherein the drum includes a drum body having a thermally conductive rear wall, and the drum body further includes a drum inlet and a drum outlet. The drum further includes a removable front wall. The inner drum space is defined by the rear wall, the front wall, and the circumferential wall. The roasting unit may further include a drum rotor, wherein the drum rotor is rotatably arranged inside the drum, and a drum rotor drive operatively coupled to the drum rotor to rotate the drum rotor. In an embodiment, the front wall is transparent.

[0011] Depending on the embodiment, the drive is fixedly attached to the drum and / or is part of the drum. Alternatively, the drive is separate from the drum. The drive may include an electric motor.

[0012] It is noted that the design described here, and in particular the removable and optionally transparent front wall, imposes a number of constraints and limitations on the overall design of the coffee roaster, which are not present in typical prior art devices. In particular, the transparent (usually made of glass, as further explained below) and / or removable front wall has the consequence that the front wall is not available for attaching heaters, sensors and openings / holes for filling and removing coffee beans, feeding and extracting hot air, etc., as discussed in more detail further below. Instead, all such features generally need to be arranged at the drum body, and in particular the rear wall of the drum.

[0013] The baking unit may further include a hot air supply device, wherein the hot air supply device includes an air heater and a positive pressure device to feed hot air into the drum. The baking unit may further include an exhaust gas extractor to extract exhaust gas from the drum. The exhaust gas extractor may include a negative pressure device.

[0014] The baking unit may further include a drum heater, wherein the drum heater is thermally coupled to the rear wall to heat the rear wall.

[0015] The coffee roaster further comprises a sensor arrangement. The sensor arrangement may comprise a roasted bean temperature sensor, wherein the roasted bean temperature sensor is configured to measure the roasted bean temperature of the coffee beans positioned inside the drum and provide a roasted bean temperature signal. The roasted bean temperature sensor may be implemented, for example, as a PT100 temperature sensor or an infrared temperature sensor.

[0016] The coffee roaster further comprises: a control unit for controlling the execution of the coffee roaster on the coffee bean roasting process. The control unit is configured to receive a control input signal as a function of time, wherein the control input signal may include a roasted bean temperature signal. The control unit is further configured to automatically generate a control output signal as a function of time in dependence on the control input signal. The control output signal comprises at least one of a drum heater control signal, a drum rotor drive control signal, and an air heater control signal and / or a positive pressure device control signal, thereby controlling the operation of at least one of the drum heater, the drum rotor drive, and the air heater and / or the positive pressure device to roast the coffee beans inside the drum according to a predetermined selected roasting profile. The selected roasting profile may include a desired roasted bean temperature and a target roasted bean temperature as a function of time.

[0017] Via the drum heater control signal, the operation of the drum heater can be controlled. Via the drum rotor drive control system, the operation of the drum rotor drive can be controlled. Via the air heater control signal, the operation of the air heater can be controlled. Via the positive pressure device control signal, the operation of the positive pressure device, in particular the operation of the intake fan as discussed further below, can be controlled.

[0018] The control unit is further configured to determine whether a roasting end condition is satisfied, wherein the roasting end condition may include that the coffee beans inside the drum have a target roasted bean temperature.

[0019] The roasting of the coffee beans is achieved by a combination of direct heat and hot air transferred to the coffee beans via the rear wall, which is particularly advantageous. During roasting, the drum rotor drive is usually activated and the drum rotor rotates so that the coffee beans inside the drum are continuously mixed and roasted in a uniform manner.

[0020] Controlling the operation of the drum heater may in particular comprise controlling the heating power of the drum heater. Advantageously, the heating power of the drum heater may be controlled in a substantially continuous manner. However, in further embodiments, the heating power may be controlled in a plurality of discrete steps and / or may be switched on and off only via the drum heater control signal.

[0021] The operation of controlling the drum rotor drive may in particular include controlling the rotational speed of the drum rotor drive, and thus the rotational speed of the drum rotor. Advantageously, the rotational speed of the drum rotor drive may be controlled in a substantially continuous manner. However, in further embodiments, the rotational speed of the drum rotor drive may be controlled in a plurality of discrete steps and / or may be turned on and off only via the drum heater control signal. Typically, the drum rotor drive may also be turned off via the drum rotor drive control signal.

[0022] Controlling the operation of the air heater may in particular comprise controlling the heating power of the air heater, for example by switching the heating power on / off and / or regulating the heating power continuously or in a plurality of discrete steps.

[0023] As discussed further below, controlling the operation of the positive pressure supply device and the optional negative pressure device is generally associated with controlling the pressure difference between the inlet side and the outlet side and / or the airflow through the positive pressure device and the negative pressure device, respectively. In the embodiment in which the positive pressure device includes an intake fan, controlling the operation of the positive pressure supply device may particularly include controlling the speed of the intake fan. Similarly, in the embodiment in which the negative pressure device includes an extractor fan, controlling the operation of the negative pressure device may particularly include controlling the speed of the extractor fan. The operation of the positive pressure supply device or the negative pressure device can advantageously be controlled in a substantially continuous manner, for example, by controlling the speed of the intake fan or the extractor fan, respectively, in a continuous manner. In other embodiments, the positive pressure supply device and / or the negative pressure supply device can be opened and closed only via corresponding control signals, without continuous regulation, regulation of the speed, or can be controlled in multiple discrete steps.

[0024] The coffee roaster according to the present disclosure has many advantageous properties, which makes it particularly suitable for use directly in stores, cafeterias, etc., and is generally roasted on demand for end users or consumers. Although the coffee roaster according to the present disclosure can be designed for processing and roasting different amounts of coffee beans, it can generally be designed for roasting about 0.5kg to 1.5kg of coffee beans, and the inner drum space can be correspondingly designed to accommodate about 0.5kg to 1.5kg of coffee beans. Compared with the roasting devices commonly used by commercial coffee roasters (the commercial coffee roasters are designed to efficiently roast a large amount of coffee beans in a uniform and generally time-saving manner), the coffee roaster according to the present invention can be advantageously used to roast significantly smaller amounts of coffee beans in a flexible manner. The type of coffee beans and the roasting process and its parameters are advantageously easily changeable batch by batch. In addition, the coffee roaster according to the present invention is suitable for use directly in stores and cafeterias because the exhaust gases have been cooled, filtered and / or passed through a catalyst, so that this is not a problem from a health and safety perspective. In addition, the coffee roaster is designed so that the operating noise is within acceptable limits.

[0025] Because the coffee bean roasting process is automatically performed under the control of the control unit, little, if any, experience and coffee roasting skills are required in order to obtain the desired result defined by the predetermined selected roasting curve. Moreover, substantially no manual observation and handling is required during roasting, which is particularly advantageous for use, for example, in a store or cafeteria. Further advantageous features and embodiments in the context of the type of application are further described below in the general description and in their respective contexts described in the drawings.

[0026] It has been found that measuring the temperature of the coffee beans (possibly together with other properties and characteristics explained further below) is particularly suitable for controlling the roasting process and automatically determining when the desired state is reached and when the roasting process is complete.

[0027] In a control environment, the desired roasted bean temperature as a function of time (which is provided as part of a selected roasting curve) can be considered as a time-dependent setpoint value, respectively as a reference variable. The control output signal or its components can be considered as a correction or actuation variable. The target roasted bean temperature and one or more optional further target values ​​(in particular the target roasted bean color as discussed further below) define the end of the roasting conditions as a stop criterion for ending the roasting process.

[0028] In addition to the rear wall, the drum body includes a circumferential wall connecting the rear wall and the front wall. The circumferential wall can be optionally formed integrally with the rear wall or formed separately. Advantageously, the circumferential wall is also heat-conductive and can be made of the same material as the rear wall or designed in the same way as the rear wall, however, this is not mandatory.

[0029] The drum has a longitudinal drum axis which is a central axis or axis of symmetry and extends through the center of the rear wall and the front wall. In the operating configuration of the coffee roaster, the longitudinal drum axis is horizontal, transverse or perpendicular to the direction of gravity. The drum rotor has a rotor axis which is coincident or aligned with the longitudinal drum axis as a common axis.

[0030] Furthermore, the drum advantageously has a drum diameter which is significantly greater than the drum length, or the extension along the drum axis, or the distance between the parallel rear wall and the front wall. Thus, the drum advantageously is disc-shaped.

[0031] All parts of a coffee roaster that come into contact with the coffee beans before, during and after the roasting process are made of food grade materials. This is particularly true for the drum and drum rotor, which must further be designed to withstand the temperatures typically exceeding 400°C that occur during roasting.

[0032] In an embodiment, the rear wall is implemented as a sandwich structure, which includes an inductively heatable outer layer in thermal contact with the drum heater, an aluminum core layer and a food-grade inner layer (coffee bean contact side, opposite to the outer layer). This design is particularly advantageous in the design of an induction heater in which the drum heater is designed to be in thermal contact with the outer layer. The core layer distributes heat substantially evenly and has low losses. Instead of aluminum, other suitable high thermal conductivity materials (such as copper) can be used for the core layer. The food-grade inner layer can be made of, for example, chrome steel or stainless steel, and can be relatively thin, or implemented as a coating. The circumferential wall of the drum rotor and the drum body is also made of food-grade material or at least coated with food-grade material. In particular, the circumferential wall can have the same design as the rear wall, and for example is also implemented as a sandwich structure as described above. The typical thickness of each layer can be, for example, between 1mm and 5mm. The expression "outer layer" refers to the outside of the rear wall, pointing away from the inner drum space, and the inner layer defines the bounding surface of the inner drum space.

[0033] The front wall is advantageously made of inert and food grade glass. The front wall is typically removably attached to the drum body in a manner that allows easy removal by an operator, optionally without the need for tools, thereby allowing easy removal for cleaning and maintenance purposes. Optionally, the inner surface of the front wall may be coated with a heat reflective and transparent coating generally known in the art, thereby reducing undesirable heat radiation and limiting the temperature of the outer surface of the front wall that is generally accessible to the user. In the operating state in which the front wall is attached to the drum compartment, the connection between the drum compartment and the front wall is advantageously airtight and / or odor-tight.

[0034] In embodiments where the front wall is opaque, it may be made from substantially the same material as the rear wall and / or circumferential wall, such as food grade stainless steel.

[0035] In other designs, the drum heater is not designed as an induction heater, but is designed as a resistive heater, a Peltier element heater or an infrared heater, for example. In such a design, the aforementioned sandwich structure architecture with an outer layer, a core layer and an inner layer may not be necessary or can be modified. In particular, in an embodiment in which the drum heater is a resistive heater, the rear wall can be implemented as a sandwich structure comprising two layers. One layer is an outer layer of aluminum or other highly thermally conductive material, in which the heating element is embedded. The other layer is an inner layer of food grade material as explained above.

[0036] The drum inlet is arranged above the longitudinal drum axis. Typically, the drum inlet is arranged at the rear wall, close to the connection with the circumferential wall. However, alternatively, the drum inlet may also be arranged in the upper region of the circumferential wall. The drum inlet is or comprises an opening, via which green coffee beans can be put into the drum for subsequent roasting. Advantageously, the inlet opening is connected to or connectable to a hopper, into which coffee beans to be roasted can be usually manually filled. Such a hopper may optionally be part of a coffee roaster. In a particularly advantageous embodiment, the drum inlet is connected to the hopper via a drum inlet baffle, which may be arranged between the hopper and the drum inlet or may be arranged at the drum inlet. The hopper is advantageously arranged above the drum inlet so that coffee beans can be transferred from the hopper to the drum by gravity.

[0037] The drum outlet is arranged below the longitudinal drum axis. Typically, the drum outlet is arranged at the rear wall, close to the connection with the circumferential wall. However, alternatively, the drum outlet can also be arranged in the lower region of the circumferential wall. The drum outlet is or includes an opening, and the roasted coffee beans can be removed from the drum via the opening. In a particularly advantageous embodiment, as further explained below, the drum outlet baffle is arranged at the drum outlet. In the embodiment discussed in further detail below, the drum outlet is further configured to receive cooling air from a cooling container when cooling the roasted coffee beans. In such a design, the drum outlet is advantageously designed to be coupled with a cooling container (particularly a cooling container inlet) in an airtight or airtight manner. Therefore, while the coffee beans are cooled, the drum can be quickly cooled, returning the drum to a temperature at which it can be safely disposed of and / or it can receive additional unroasted beans for subsequent roasting processes.

[0038] In order to feed hot air into the drum, the drum body (advantageously the rear wall) includes a hot air supply device opening as an interface between the hot air supply device and the inner drum space to establish a fluid communication or fluid connection between the hot air supply device and the inner drum space. In some specific embodiments, the hot air supply device opening is identical to or integrated with the drum outlet.

[0039] The heating element of the hot air supply device is usually implemented as a resistive heating element, but in principle it can also be implemented differently, in particular as an induction heating element or a gas heating element, a Peltier element, etc. Via the positive pressure device, the hot air is actively blown into the drum or pressed into the drum. In a typical embodiment, the positive pressure device is implemented as an intake fan or a blower. However, in an alternative embodiment, the positive pressure device is implemented as or includes, for example, a pressurized air tank, a compressor, etc. In some embodiments, there may be a flow control element, such as one or more valves, a throttle valve, etc. The positive pressure device can usually be coupled to the inner drum space via an appropriate pipe for connecting to the hot air supply device opening.

[0040] In order to extract the exhaust gases from the inner drum space, the drum body (advantageously the rear wall) comprises an exhaust gas extraction opening as an interface between the inner drum space and the exhaust gas extractor to establish fluid communication between the exhaust gas extractor and the inner drum space. Like the inlet opening, the exhaust gas extraction opening is advantageously arranged in the upper region of the drum body, above the longitudinal drum axis. Advantageously, a coffee bean holding element (in particular a coffee bean holding element in the form of a porous plate or a grid) is arranged at the exhaust gas extraction opening. The opening of the coffee bean holding element is sized so that the exhaust gases can pass through it without substantial resistance, and the dregs separated from the coffee beans during roasting can also pass through, but the coffee beans are retained in the drum.

[0041] The exhaust gas extractor includes a negative pressure device to actively extract the exhaust gas by suction. In a typical embodiment, the negative pressure device is implemented as an extractor fan or an extractor blower. However, in an alternative embodiment, the negative pressure device is implemented as a vacuum pump, such as a water jet pump. The negative pressure device can in principle be directly coupled to the inner drum space using, for example, appropriate pipes for connecting to the exhaust gas extraction opening. However, in other and particularly advantageous embodiments, the negative pressure device is fluidically coupled to the inner drum space via an exhaust gas treatment unit as an intermediate element, as further explained in more detail below. In addition, the exhaust gas extractor can include a chimney, which can particularly be fluidly arranged downstream of the negative pressure device (e.g., an extractor fan). Note that the negative pressure device can also be considered to be part of the exhaust gas treatment unit, as further discussed below in the context of specific embodiments.

[0042] In embodiments discussed further below, the exhaust extractor is further configured and operable to extract or remove cooling air used to cool roasted coffee beans in the cooling unit.

[0043] In an embodiment, the sensor arrangement further comprises one or more additional sensors as explained below:

[0044] The sensor arrangement may include a roasted bean color sensor, wherein the roasted bean color sensor is configured to measure the roasted bean color of the coffee beans located inside the drum and provide a roasted bean color signal, wherein the control input signal includes the roasted bean color signal. The roasted bean color sensor is typically an optical sensor known in the prior art, or may be implemented, for example, by a camera in combination with corresponding image processing logic and / or image processing firmware / software code. In particular, the roasted bean color sensor may be arranged in or at the circumferential wall or the rear wall. The roasted bean color sensor itself is advantageously not arranged inside the drum, but is configured to sense the roasted bean color of the coffee beans via a window or hole in the circumferential wall or the rear wall. In an embodiment comprising a roasted bean color sensor, the end-of-roasting condition may include that the coffee beans inside the drum have a target roasted bean color.

[0045] The sensor arrangement may comprise a rear wall temperature sensor, wherein the rear wall temperature sensor is configured to measure a rear wall temperature of the rear wall and to provide a rear wall temperature signal, wherein the control input signal comprises the rear wall temperature signal.

[0046] The sensor arrangement may comprise a drum air temperature sensor, wherein the drum air temperature sensor is configured to measure a drum air temperature inside the drum and to provide a drum air temperature signal, wherein the control input signal comprises the drum air temperature signal.

[0047] The sensor arrangement may comprise an inlet air temperature sensor, wherein the inlet air temperature sensor is configured to measure an inlet air temperature of hot air fed into the drum and to provide an inlet air temperature signal, wherein the control input signal comprises the inlet air temperature signal.

[0048] The sensor arrangement may comprise an air humidity sensor, wherein the air humidity sensor is configured to measure the extracted air humidity of air extracted from the drum and to provide an air humidity signal, wherein the control input signal comprises the air humidity signal.

[0049] The sensor arrangement may comprise an air flow sensor, wherein the air flow sensor is configured to measure an extraction air flow rate of air extracted from the drum and to provide an air flow signal, wherein the control input signal comprises the air flow signal.

[0050] The sensor arrangement may comprise a crack detection sensor, wherein the crack detection sensor is configured to detect the presence of first and / or second cracks in the coffee beans during roasting and to provide a crack detection signal, wherein the control input signal comprises the crack detection signal. The crack detection sensor is configured and arranged to detect the presence of the first and / or second cracks based on a mechanical wave generated by the crack. The detected mechanical wave may be an acoustic wave and the crack detection sensor may be a loudspeaker. Alternatively or additionally, the mechanical wave may be structure generated and detected at the drum body, in particular the rear wall and / or the circumferential wall. In such an embodiment, the crack detection sensor may be an acceleration sensor or a vibration sensor, for example based on piezoresistance or capacitance.

[0051] The sensors described herein are found to provide particularly useful information for monitoring and / or supervising a baking process in the context of an automated setting, and some or all of them may be used accordingly. Additional sensors that may be present in some embodiments are discussed further below in their respective contexts.

[0052] In an embodiment, the sensor comprises one or more pressure sensors, for example comprising an air outlet pressure sensor and / or an air inlet pressure sensor. A given pressure sensor can measure an absolute pressure, a relative pressure and / or a pressure difference. One or more pressure sensors are arranged to measure the air pressure in one or more positions in the coffee roaster, in particular the air pressure of the air flowing into and / or out of the drum. For example, the sensor comprises a pressure sensor arranged upstream of the drum, the pressure sensor being configured to measure the relative pressure of the inlet air relative to the ambient pressure. Additionally, the sensor may comprise a pressure sensor arranged downstream of the drum, the pressure sensor being configured to measure the relative pressure of the outlet air relative to the ambient pressure. One or more pressure sensors are each configured to provide a control signal indicative of the measured pressure. Using the control signal indicative of the pressure sensor, a temperature difference can be determined, and a temperature difference can be determined between two or more positions, the temperature difference indicating, for example, the flow rate of the air between the two positions.

[0053] In an embodiment, the control output signal comprises a negative pressure device control signal, thereby controlling the operation of the negative pressure device of the exhaust gas extractor. During roasting, the positive pressure device and the negative pressure device can be advantageously controlled in a coordinated manner so that the airflow of hot air fed to or entering the drum corresponds to the airflow of the exhaust gas extracted from or leaving the drum from the drum. In this way, a continuous flow is achieved and any rejection is prevented. In an embodiment comprising a cooling unit (wherein the cooling air is transferred or fed into the drum after cooling the roasted coffee beans and is extracted by the exhaust gas extractor), the exhaust gas extractor (e.g., an extractor fan) can be controlled to operate at a power that is generally high and possibly maximum. In this way, it is ensured that air is safely extracted from the drum via the air extractor and that rejection does not occur.

[0054] In an embodiment, the coffee roaster comprises a drum inlet damper, wherein the drum inlet damper is arranged to alternately open or close the drum inlet. In such an embodiment, the selected roasting profile may include a selected pre-roasting condition, and the control unit may be configured to generate a pre-roasting control output signal as part of the control output signal, and determine whether the selected pre-roasting condition is met based on the control input signal, and control the drum inlet damper to open the drum inlet when the selected pre-roasting condition is met. The control unit is further configured to control the drum inlet damper to close the drum inlet when the coffee beans are transferred or filled into the drum, and to maintain the drum inlet damper closed during roasting. Accordingly, the drum inlet damper is controlled to only temporarily open the drum inlet for filling or transferring the coffee beans into the drum, but to maintain it closed in other cases.

[0055] The drum inlet baffle is arranged at the drum inlet or between the hopper and the drum inlet, so that in a configuration in which the coffee bean inlet baffle is open, coffee beans can be filled into the drum or the inner drum space respectively. In a configuration in which the inlet baffle is closed, the passage from the hopper into the drum is blocked. The inlet baffle is advantageously designed to seal the passage from the inner drum space to the hopper in an airtight manner. Thereby, exhaust gases are prevented from leaving the inner drum space via the inlet opening during roasting, but only leave the inner drum space via the exhaust gas extraction opening. The inlet baffle further comprises an inlet baffle actuator, such as an electromagnet or a motor that is operatively cooled together with the control unit.

[0056] Pre-baking conditions usually include drum air temperature and drum body temperature, particularly rear wall temperature, which will occur at the beginning of baking depending on the desired baking. In another embodiment, it only includes the drum body temperature that will occur at the beginning of baking.

[0057] The embodiment with a controlled inlet damper is advantageous both with regard to the convenience and the quality of the roasting process. The user can fill the hopper with green coffee beans at substantially any point in time, for example after turning on the coffee roaster. If the pre-roasting conditions are met, the coffee beans in the hopper are transferred to the drum by automatically opening the drum or the inlet damper. The time until the pre-roasting conditions are met is also referred to as pre-heating.

[0058] During preheating, the drum rotor drive and the drum rotor are typically controlled to operate separately to ensure a uniform temperature distribution within the drum. In addition, the control unit is advantageously configured to control the drum rotor drive during the transfer of coffee beans from the hopper into the drum, or while the drum inlet opening is opened to rotate at a generally reduced speed, thereby ensuring that the drum rotor transports coffee from the drum inlet opening into the inner drum space and that the drum inlet opening is not blocked. When the drum inlet opening is closed again by the drum inlet damper, roasting begins and the drum rotor drive is controlled according to the selected roasting profile. Preheating may include a holding phase after the pre-roasting conditions are met, in which the relevant parameters (particularly the rear wall temperature or the drum air temperature) are maintained constant before the inlet damper is opened and roasting begins.

[0059] In an embodiment, the coffee roaster comprises a drum outlet damper, wherein the drum outlet damper is arranged to alternately open or close the drum outlet. In such an embodiment, the control unit can be configured to control the drum outlet damper to open the drum outlet when the roasting end condition is met.

[0060] This type of embodiment has the particular advantage that the coffee beans automatically leave the drum when the roasting end conditions are met, and in particular the coffee beans have a target roasted bean temperature, and are not further roasted in an uncontrolled and undesirable manner due to the hot rear wall and the hot air inside the drum.

[0061] The drum outlet damper may comprise a flap similar to the drum inlet damper explained above, but may also be, for example, a removable perforated plate or a slide. The drum outlet damper further comprises an outlet damper actuator, such as an electromagnet or motor cooled in operation with a control unit.

[0062] In the configuration where the drum outlet is open, roasted coffee beans can be removed from the inner drum and advantageously fall out of the drum by gravity. During this process, the drum rotor drive is advantageously controlled to be active and rotate the drum rotor, which pushes the coffee beans out of the inner drum space.

[0063] In an embodiment, a coffee roaster comprises a cooling unit. However, it is noted that a cooling unit according to the present disclosure may also be implemented and used in the context of other types of coffee roasters.

[0064] The cooling unit comprises a cooling container having a cooling container inlet. The cooling container inlet can be coupled with the drum outlet via a drum outlet baffle.

[0065] The cooling unit may further include a cooling medium supply. The cooling medium supply may include a cooling air supply, wherein the cooling air supply is fluidly coupled to the internal cooling container space to feed cooling air into the cooling container. Alternatively or additionally, the cooling medium supply may include a cooling water supply.

[0066] The cooling water supply may comprise a nozzle arrangement, wherein the nozzle arrangement is configured to spray cooling water onto the coffee beans inside the cooling container.

[0067] Via the cooling unit, the coffee beans can be cooled down in a well-defined and controlled manner. In particular, it is often desirable to cool the coffee beans down quickly, without however getting them wet. This can be achieved in embodiments comprising both a cooling air supply and a cooling water supply. However, in some designs, either one may be sufficient.

[0068] In an embodiment, the cooling unit may further include a cooling rotor drive operatively coupled to the cooling rotor to rotate the drum rotor. Additionally, in an embodiment, the cooling vessel may include a cooling vessel outlet. In alternative embodiments, there is no dedicated cooling vessel outlet and / or there may be no cooling rotor and cooling rotor drive.

[0069] The cooling unit can be coupled to the drum outlet opening in particular via a drum outlet baffle, so that the drum outlet baffle alternately connects the cooling unit to the drum space when the drum outlet opening is open, or disconnects the cooling unit from the drum space when the drum outlet opening is closed, and the drum outlet baffle can also be considered or used as a cooling container inlet baffle accordingly. Therefore, only when the drum outlet baffle is open can the roasted coffee beans be removed from the drum and transferred to the cooling container.

[0070] The cooling air supply device may in particular comprise a cooling fan or a cooling blower, which is coupled to the cooling container interior space to actively blow or squeeze air into the cooling container interior space. Instead of a cooling fan, the cooling air supply device may, for example, comprise an air pump or a compressor to force air into the cooling container interior space. In a typical embodiment, the cooling air temperature is typically the ambient air temperature. However, optionally, the cooling air supply device may comprise a dedicated cooling device for cooling the cooling air down.

[0071] Via the cooling water supply, the coffee beans are not actually wetted. Therefore, the nozzle arrangement advantageously includes a plurality of nozzles that generate a mist atmosphere inside the cooling container. The nozzle arrangement is advantageously positioned at or above the top of the cooling container. The cooling water supply may include a cooling water pump to provide cooling water to the nozzle arrangement, and / or may operate under the line pressure of a common water supply. In addition, the cooling water supply may include a cooling water tank arranged above the cooling container so that water is forced into the nozzle from the cooling water tank by gravity. The cooling water supply may include a nozzle control valve that is operatively coupled to a control unit via a nozzle control valve control signal and controlled by the control unit. As mentioned above, the nozzle control valve control signal may be part of a control output signal. Such a nozzle control valve may be a shut-off valve or a continuous control valve for continuously controlling the water supply to the nozzle arrangement. In order to prevent the coffee beans from actually getting wet, the cooling water supply device is advantageously controlled to be activated only for a coffee bean temperature above a wetting temperature threshold, in particular 100° C., and to be shut down, in particular by completely closing the nozzle control valve, when the coffee bean temperature drops below the wetting temperature threshold indicated by the cooling bean temperature sensor.

[0072] In a specific embodiment including a cooling unit, the cooling unit may further include a cooling container outlet damper, wherein the cooling container outlet damper is configured to alternately open or close the cooling container outlet. The control unit of such an embodiment may be configured to control the cooling container outlet damper to close the cooling container outlet during cooling and open the cooling container outlet when cooling is completed.

[0073] The cooling container outlet damper may comprise a cover sheet and a cooling container outlet damper actuator, such as an electromagnet or a motor cooled in operation with the control unit. When the outlet damper is open, coffee beans may fall into the outlet container. The control unit is advantageously designed to control the cooling container outlet damper to open the cooling container outlet only for removing coffee beans from the cooling container, and to close the cooling container outlet in other cases and in particular during cooling.

[0074] During cooling of the coffee beans, the coffee beans may be continuously moved by the cooling rotor to ensure uniform exposure of the coffee beans to the cooling medium and / or cooling media, in particular cooling air and / or cooling water as mentioned above.

[0075] The operation of the cooling rotor drive and the cooling water supply device and / or the cooling air supply device can be controlled by a control unit, which can be configured to generate a cooling rotor drive control signal and a cooling air supply device control signal and / or a cooling water supply device control signal. During cooling, the cooling air supply device and / or the cooling water supply device can be controlled to operate continuously and in a constant manner. However, advantageously, the cooling air supply device and / or the cooling water supply device are controlled in a changing manner via a time-varying control signal as a function of time, thereby changing the cooling performed by air and / or cooling water over time during cooling. The control parameters for generating the cooling rotor drive control signal and the cooling air supply device and / or the cooling water supply device as a function of time can be stored as fixed parameters by the control unit. However, advantageously, the control parameters for generating one or more cooling rotor drive control signals and the cooling air supply device and / or the cooling water supply device can be part of the selected baking curve and thus vary depending on the selected target baking curve. The cooling rotor drive control signal and the cooling air supply device control signal and / or the cooling water supply device control signal can be part of the control output signal generated by the control unit.

[0076] Additionally, the control unit may be configured to switch the cooling rotor drive on and off in a binary manner. In an alternative embodiment, the control unit may be configured to control the operation of the cooling air supply means and / or the cooling water supply means in a varying manner as a function of time during the cooling period, thereby varying the cooling performed by the air and / or cooling water over time during the cooling period.

[0077] As explained previously, when the optional cooling container outlet damper is opened for removing coffee beans from the cooling container and transferring them to the outlet container, the cooling rotor drive is advantageously started and the cooling rotor rotates, thereby ensuring that all coffee beans are moved to the cooling container outlet.

[0078] In other embodiments of the cooling unit with cooling rotor and cooling rotor drive, the cooling rotor is not arranged inside the cooling container. Instead, the cooling rotor can be formed integrally with the cooling container. In such an embodiment, the cooling container is rotatable and is coupled with the cooling drive to rotate the cooling container. In such an embodiment, the cooling container can include a stirring element, such as a thin slice or a rib, which is arranged inside the inner space of the cooling container and stirs the coffee beans when the cooling container rotates.

[0079] In an embodiment, when the cooling end condition is met, the cooling is considered to be complete. Meeting the cooling end condition can be detected in particular based on one or more cooling sensor signals, wherein the one or more cooling sensor signals are generated by one or more corresponding cooling sensors of the cooling unit. In particular, the cooling unit may include a cooling bean temperature sensor, wherein the cooling bean temperature sensor is configured to measure the cooling bean temperature of the coffee beans in the cooling container, and provide a corresponding cooling bean temperature signal, wherein the cooling end criterion includes the cooling bean temperature reaching or falling below a predetermined target cooling bean temperature. In addition, the cooling unit may additionally or alternatively include a cooling bean color sensor, wherein the cooling bean color sensor is configured to measure the cooling bean color of the coffee beans inside the cooling container, and provide a corresponding cooling bean color signal, wherein the cooling end criterion includes the cooling bean color assuming a predetermined target cooling bean color. In some embodiments, the cooling end condition, in particular the target cooling bean temperature and / or the target cooling bean color can be fixed. However, advantageously, they are part of the selected roasting curve. One or more cooling sensor signals, in particular the cooling bean temperature signal and / or the cooling bean color signal can be part of the control input signal, and one or more cooling sensors, in particular the cooling bean temperature sensor and / or the cooling bean color sensor can be part of the sensor arrangement. In another embodiment, the cooling of the coffee beans is time-controlled, and the cooling end criterion is the lapse of a predetermined cooling time span after the cooling starts. When the cooling is completed, the control unit can provide a corresponding indication and / or control the cooling container outlet baffle to release the coffee beans.

[0080] In a particular embodiment comprising a cooling unit, the cooling container is fluidically coupled to the inner drum space of the drum, in particular in a fluid-tight manner, thereby enabling cooling air to be transferred from the cooling container into the drum and to be extracted from the drum by means of an exhaust air extractor. Such a design is particularly advantageous if only cooling air, but no cooling water, is foreseen as a cooling medium. In such a design, the exhaust air extractor serves the additional purpose of extracting the cooling air in a controlled manner during cooling.

[0081] The fluid coupling of the cooling container and the drum space can be in particular via the drum outlet. In such a design, the drum outlet is used to remove the roasted coffee beans from the drum and transfer them to the cooling container, and subsequently to remove the cooling air from the cooling container and transfer or feed it into the drum. Note that in this phase, there are no coffee beans in the drum. In such an embodiment, the outlet baffle is usually controlled to open during cooling. However, in another variant, a separate fluid coupling is foreseen between the drum and the cooling container for removing the cooling air from the cooling container and transferring or feeding it into the drum.

[0082] In an embodiment, the cooling container may be a removable tray configured to be removed when the cooling of the beans is completed, wherein the beans are in the tray. The cooling container may be arranged in a drawer. In such a design, a dedicated cooling container outlet baffle may be omitted. The tray may be open in particular at the upper side and / or may have a removable or openable lid. An opening may be provided in such a lid for coupling with the drum outlet. Alternatively, the tray is open at its upper side. As mentioned above, the fluid-tight coupling may be achieved by means of a seal, which may be part of the cooling container, such as the tray and / or the housing of the coffee roaster. The sides and / or bottom of the tray are perforated with air holes, which are sized so that the beans cannot pass through. The tray is configured so that the perforated sides and / or bottom of the tray do not completely contact any adjacent surface, respectively, thereby allowing air to enter the tray unimpeded through at least some of the air holes. In an embodiment, the cooling container is a bean tray as discussed further below. The drawer may include a scale configured to measure the weight of the tray so that the weight of the beans in the tray can be determined. In addition, the drawer may include an insert configured to receive cooling air from the cooling air supply and guide the cooling air into the tray. In particular, the insert is configured to guide the cooling air so that it flows into the tray through the perforations, thereby cooling the beans. In a preferred example, the cooling container (in particular the insert) includes a seal configured to achieve a fluid-tight coupling with the cooling air supply.

[0083] In an embodiment, a coffee roaster comprises an exhaust gas treatment unit. However, it is noted that the exhaust gas treatment unit according to the present disclosure may also be implemented and used in the context of other types of coffee roasters. In a specific embodiment, the exhaust gas treatment unit may include a water tank, which is designed to be filled with water until a filling level, wherein the water tank has a water tank air inlet and a water tank air outlet. The water tank air inlet is fluidly coupled to the exhaust gas extraction opening and, correspondingly, to the inner drum space. The water tank air inlet is arranged below the filling level of the water tank. The water tank air outlet is arranged above the filling level. The exhaust gas treatment unit may further include a clean water supply device for supplying clean water into the water tank and a waste water discharge device for discharging waste water from the water tank.

[0084] The extractor fan as explained above is advantageously arranged fluidically downstream of the water tank and fluidically coupled to the water tank air outlet.The water tank is thus fluidly arranged between the drum and the extractor fan.

[0085] In operation, the extractor fan generates an underpressure or suction pressure in the air volume above the filling level and simultaneously stirs the water. Via coupling with the inner drum space, due to the arrangement of the water tank air inlet, the exhaust gases are sucked into the water tank and enter the water tank below the filling level, and the water dissolves and accordingly removes smoke and its components from the exhaust gases and simultaneously cools the exhaust gases. The cooled exhaust gases rise to the water surface (as defined by the filling level) in the form of bubbles and are sucked away by the extractor fan. Inside the water tank, and usually below the filling level, a bubble intensifier can be arranged. The bubble intensifier can be realized by a perforated plate that extends substantially over the entire side surface area of ​​the water tank. The bubble intensifier divides larger air or air bubbles into smaller bubbles, thereby improving the smoke removal and cooling efficiency.

[0086] In some embodiments, the coffee roaster includes a grounds separator. Grounds separators are generally used for the purpose of separating grounds from exhaust gases. In a specific embodiment including an exhaust gas treatment unit having a water tank and a bubble intensifier as discussed above, the holes in the perforated plate used as the bubble intensifier are sized small enough to prevent the grounds from passing through. In such an embodiment, the grounds enter the water tank with the exhaust gases and remain in the water tank below the bubble intensifier until it is removed manually or by flushing the water tank. In such an embodiment, the bubble intensifier also serves as a grounds separator.

[0087] In a further embodiment, a scum separator may be arranged between the drum and the water tank, in particular between the exhaust gas outlet and the water tank air inlet. Such a scum separator may comprise a mechanical scum retaining filter, such as a mesh or a porous plate, which is passed by the exhaust gas and prevents the scum from passing. When flushing, the scum may be removed from the water tank together with the waste water, and / or may be removed manually.

[0088] In an embodiment, the bypass line is arranged so that the cooling air leaving the drum during cooling bypasses the slag separator. For example, a first end of the bypass line is connected upstream of the slag separator, such as between the exhaust gas outlet and the slag separator. The first end of the bypass line is connected at a first coupling point, which may include one or more valves configured to direct the cooling air through the bypass line during cooling. The second end of the bypass line is connected downstream of the slag separator, such as between the slag separator and the catalyst, which is described in more detail below. In particular, the second end of the bypass line is connected at a second coupling point between the slag separator and the filter, as described in more detail below.

[0089] In an embodiment, a water temperature sensor may be arranged in the water tank and below the filling level for monitoring the water temperature. The water temperature sensor is operatively coupled to the control unit. The water temperature sensor provides a water temperature sensor signal, which may be part of the input control signal. The control unit may be configured to determine when the water tank should be flushed and the water replaced based on the water temperature control signal. The control unit may in particular be configured to compare the water temperature with a water temperature threshold value of, for example, 70 degrees Celsius substantially continuously. The water temperature reaching or exceeding the water temperature threshold value indicates that the water tank should be flushed and the water inside the water tank should be replaced.

[0090] For flushing the water tank and changing the water, as mentioned above, there may be a fresh water inlet supply and a waste water drain, and coupled to the inner volume of the water tank via a fresh water supply valve and a waste water drain valve. The waste water supply valve and the waste water drain valve may be controlled by a control unit, thereby allowing automatic flushing of the water tank and changing the water as required.

[0091] In order to ensure that the water tank is filled to the desired filling level initially and after flushing, a filling level sensor operatively coupled to the control unit may be provided. The filling level sensor may in particular be a float gauge. Alternatively, the filling level sensor may be implemented differently, for example by one or more resistance-based sensors, capacitive sensors, optical sensors, etc. The control unit may be configured to control the clean water supply valve and / or the waste water discharge valve according to the signal provided by the filling level sensor. In particular, the control unit may be configured to control the clean water inlet valve to open after the water tank is completely emptied until the filling level sensor indicates that the desired filling level has been reached. In a further embodiment, the filling level sensor is a water flow sensor, which is arranged in or at the clean water supply, and the control unit is configured to determine the filling level according to the amount of water fed into the water tank.

[0092] In an alternative embodiment, cleaning of the water tank and replacement of the water may be done manually, for example, with a user indication provided if the water temperature reaches or exceeds a water temperature threshold. While manual replacement of the water is typically done between roasting of coffee bean batches or when the coffee roaster is not in operation, as previously explained, automatic flushing and water replacement under the control of the control unit may also be performed during an ongoing roasting process.

[0093] Via the water tank air outlet, the exhaust air is drawn off from the water tank. In embodiments in which a condenser and an exhaust air filter are present, the exhaust air filter is advantageously arranged fluidically downstream of the condenser, so that the air is first dried after leaving the water tank and subsequently filtered. Via the filter, undesirable odors and / or stink are removed from the exhaust air. In this way, the coffee roaster can also be operated indoors without the occurrence of undesirable odors or stink and without the need for additional exhaust air treatment devices.

[0094] In some embodiments of the exhaust gas treatment unit, the exhaust gas treatment unit includes a condenser, wherein the condenser is fluidly coupled to the water tank air outlet so that the air extracted from the water tank passes through the condenser. As the exhaust gas leaves the water tank, it is typically saturated with moisture, which is removed by the condenser, thereby drying the exhaust gas. The condenser accordingly acts as a dehumidifier. In addition, the condenser is advantageously fluidly arranged between the water tank air outlet and the extractor fan so that the exhaust gas passes through the condenser before the extractor fan.

[0095] In an embodiment of the exhaust gas treatment unit, the exhaust gas treatment unit comprises an exhaust gas filter. The exhaust gas filter is fluidly coupled to the water tank air outlet so that the air extracted from the water tank passes through the exhaust gas filter. The exhaust gas filter removes undesirable odorous substances from the exhaust gas. In addition, the exhaust gas filter is advantageously fluidly arranged between the water tank air outlet and the extractor fan so that the exhaust gas passes through the exhaust gas filter before the extractor fan.

[0096] In the embodiment where there are both a condenser and an exhaust filter, the condenser and the exhaust filter may be arranged fluidically in series between the water tank air outlet and the extractor fan. The arrangement may be such that the exhaust gas first passes through the condenser after leaving the water tank, followed by the exhaust filter.

[0097] In an embodiment including a scum separator, the scum separator may include a cyclone separator for separating scum and a scum collector, for example in the form of a drawer. The control unit may control the cyclone separator via a corresponding cyclone control signal. The cyclone separator may also be a passive cyclone separator, such that the shape of the device causes air circulation into the cyclone and maintains a spiral air vortex (i.e., a cyclone). Particles in the air leave the cyclone separator through an opening at the bottom of the cyclone separator, and air escapes from the cyclone separator through an opening at the top. Such a passive cyclone separator does not require any active element to start or maintain a cyclone.

[0098] In an embodiment, the coffee roaster comprises a grounds separator temperature sensor, which is configured to measure directly or indirectly the air temperature inside the grounds separator. The grounds separator temperature sensor may be arranged at the grounds separator, for example attached to the housing of the grounds separator, the temperature of the housing indicating the air temperature inside the grounds separator. The grounds separator temperature sensor may be arranged inside the grounds separator, thereby directly measuring the air temperature inside the grounds separator. The grounds separator temperature sensor may be arranged fluid downstream of the grounds separator, thereby measuring the air temperature of the air leaving the grounds separator. The grounds separator temperature sensor provides a control signal to the control unit. The control unit is configured to determine whether there is a fire in the coffee roaster depending on the temperature measured by the grounds separator temperature sensor. In particular, a temperature measured by the grounds separator temperature sensor exceeding a fire temperature threshold is considered to indicate a fire. Additionally, if the temperature measured by the grounds separator temperature sensor rises faster than a predetermined temperature rise rate, this is considered to indicate a fire. A fire will usually burn the slag in the slag drawer.

[0099] In an embodiment, the coffee roaster comprises a fire extinguisher. The fire extinguisher is arranged so that it can extinguish a fire in a grounds separator, preferably including a grounds drawer. The fire extinguisher may be attached or connected to the grounds separator and / or the grounds drawer. The fire extinguisher is activated when the control unit detects a fire. The fire extinguisher may extinguish the fire using water, CO2, foam or other fire extinguishing means. Additionally, the control unit may be configured to generate an alarm to warn a user of the coffee roaster of the fire, for example by generating an alarm signal that is transmitted to an acoustic transducer to warn the user. In addition, the alarm signal may be connected to a lighting element of the coffee roaster to visually indicate a fire condition. In addition, the control unit may be configured to turn off all heating elements and reduce the airflow through the coffee roaster to a minimum level that is determined so that the heating elements are not damaged.

[0100] In an embodiment comprising an exhaust gas treatment unit, the exhaust gas treatment unit comprises a catalyst configured to remove odorous substances from the exhaust gas extracted from the drum. In addition to the aforementioned water-based exhaust gas treatment, in particular in series with the water-based exhaust gas treatment, a catalyst and advantageous auxiliary components can be provided, as discussed further below. However, in general, an exhaust gas treatment unit comprising a catalyst can be foreseen as an alternative. It has the particular advantage that odorous or smelly substances can be removed from the exhaust gas without the need for the typically complex and cumbersome cooling water treatment. In particular, the catalyst can be configured to remove carbon monoxide from the exhaust gas.

[0101] In a specific embodiment comprising an exhaust gas treatment unit with a catalyst, the exhaust gas treatment unit comprises an exhaust gas heater and an exhaust gas cooler, the exhaust gas heater being fluidly arranged upstream relative to the catalyst and the exhaust gas cooler being fluidly arranged downstream relative to the catalyst. The exhaust gas heater, the catalyst and the exhaust gas cooler are typically fluidly arranged in series. The exhaust gas heater is activated and used during the baking process, in particular during the final stages of the baking process, to heat the exhaust gas that has left the drum to an optimal temperature for catalytic cleaning or removal of odorous substances via the catalyst. The exhaust gas heater can heat the exhaust gas to a temperature between 200° and 400°, preferably between 250° and 300°C. In the early stages of the baking process, the exhaust gas heater can typically be deactivated or turned off.

[0102] The exhaust gas heater may be controlled by the control unit via an exhaust gas heater control signal. The exhaust gas heater control signal may be part of the control output signal. The control operation of the exhaust gas heater may in particular include controlling the heating power of the exhaust gas heater, for example by turning the heating power on / off and / or adjusting it continuously or in a plurality of discrete steps. Additionally, an exhaust gas temperature sensor may be arranged at or downstream of the exhaust gas heater to measure the temperature of the heated exhaust gas. An exhaust gas cooler is provided to cool the significantly heated exhaust gas leaving the catalyst. For example, the exhaust gas cooler may include a gas cooler, wherein the exhaust gas passes through a duct, which becomes hot and then dissipates the heat to the environment via convection and radiation. Additionally, one or more fans may be arranged in the coffee roasting and configured to blow and / or draw air over the exhaust gas cooler, in particular the duct of the gas cooler, to increase the heat dissipation rate and thereby reduce the temperature of the exhaust gas leaving the coffee roaster.

[0103] In addition to the above-described arrangements, or in lieu of the above-described arrangements, the exhaust gas treatment unit may comprise further odorous and / or harmful substance removal devices. In particular, a mechanical particle filter through which the exhaust gases pass can be foreseen. In addition to the mechanical filter, or in lieu of the mechanical filter, the particle filter may comprise an electrostatic particle filter. The electrostatic particle filter may be configured to retain particles by means of electrostatic attraction or repulsion. In addition, the particle filter may be or may comprise an activated carbon filter. In an example, the electrostatic particle filter comprises a glass fiber filter. In an embodiment, the exhaust gas treatment unit is configured such that the removal device, in particular the mechanical particle filter, is accessible and removable and is therefore easily replaceable.

[0104] The slag separator and the exhaust gas treatment unit are usually arranged fluidly between the drum outlet and the exhaust gas extractor. Advantageously, the slag separator is arranged fluidly upstream of the exhaust gas treatment unit so that the exhaust gas is free or substantially free of slag when entering the exhaust gas treatment unit.

[0105] In an embodiment, the coffee roaster includes a green coffee bean scale for measuring the weight of green coffee beans before filling green coffee beans into the drum. In addition, in an embodiment, the coffee roaster may include a roasted bean scale for measuring the weight of roasted coffee beans after roasting. In an embodiment, the coffee roaster includes a bean scale used as both a green bean scale and a roasted bean scale. The bean scale can be integrated into a drawer or container. As explained above, a drawer or container can be used to fill green coffee beans into a drum or hopper. The drawer or container and the box and the bean scale can be configured to measure the weight of green coffee beans before filling green beans into a drum or hopper. After roasting, the drawer or container can be placed at or below the cooling container outlet so that roasted and optionally dried coffee beans fall into or are released into the drawer or container, and the roasted bean weight of roasted, cooled and optionally dried coffee beans is measured.

[0106] Advantageously, the green bean scale and the roasted bean scale or the bean scale as a combination of the green bean scale and the roasted bean scale is operatively coupled to the control unit for transmitting the measured green bean weight or roasted bean weight to the control unit. In some embodiments, the control unit may be configured to store and / or process the green bean weight and the roasted bean weight. Optionally, the control unit may be configured to transmit the green bean weight and / or the roasted bean weight to a remote computer system, as further explained below. If applicable, the control unit and / or the remote computer system may be further configured to determine whether the roasting and drying of the coffee beans is successful based on the difference and / or ratio of the green bean weight to the roasted bean weight. In the affirmative case, the roasted bean weight is more than 10% lower than the green bean weight.

[0107] In order to control the operation of the coffee roaster and provide information to the user (such as status information, warnings and / or alarms), the control unit may include and / or may be designed to be operatively coupled to a user interface unit. The user interface unit may be part of the coffee roaster or may be provided in whole or in part as a separate user interface device. In a particular embodiment, the user interface device is a general purpose computing device, such as a smartphone, a tablet computer, or a laptop or desktop computer. In an embodiment, the control unit may be fully or partially implemented by such a general purpose computing device.

[0108] In an embodiment, the user interface device and the control unit can be configured to communicate via a wireless communication interface, such as a Bluetooth and / or Wifi interface and / or an interface for communicating via a mobile communication network, such as according to the 5G standard. Alternatively or additionally, the user interface device and the control unit can be configured to communicate via a wired interface, such as one or more USB buses (e.g., mini-USB, micro-USB, USB, USB-C) or a wired LAN interface. In addition, in some embodiments, the control unit and the user interface device can be configured to communicate via the Internet. For this purpose, the user interface device and the control unit can be configured for wired and / or wireless Internet access. The user interface device can further be configured to communicate with a remote computer system via the Internet.

[0109] Controlling the execution of the roasting process according to the selected roasting profile is typically a closed-loop control, wherein a control output signal is generated or modified substantially in real time based on a control input signal as a feedback signal and the selected roasting profile. In a typical embodiment, the closed-loop control is a multiple-input multiple-output control, wherein the signals provided by the sensors of the sensor arrangement are combined to form the control input signal.

[0110] A roasting curve, and in particular a selected roasting curve, may include the desired roasted bean temperature as a function of time, for example in the form of one or more interpolation functions, such as spline curves, or their parameters, and / or as a lookup table of time-temperature pairs. In addition, a roasting curve may only include temperatures that should be approached one after another.

[0111] The generation of the output control signal or its components by the control unit can be based on a classical controller design, for example a RID controller, and / or on a fuzzy control algorithm and / or a neural network, for example.

[0112] During the roasting process, the control parameters are not necessarily constant over time in each case, but may, for example, vary or be modified in a predetermined manner as a function of time and / or may be changed according to one or more rules forming part of a roasting profile, in particular a selected roasting profile, which depends on the occurrence of characteristic events as explained below.

[0113] The control input signal may include one or more sensor signals, which directly and / or indirectly indicate the temperature conditions inside the drum, in particular a roasted bean temperature signal, a rear wall temperature signal, an inlet air temperature signal and an airflow signal. In addition, the control input signal may include one or more sensor signals indicating the stage of the roasting process and / or a specific characteristic event during the roasting process, in particular a roasted bean color signal and / or a crack detection signal as mentioned above. Such characteristic events can also be derived from temperature indicating sensor signals as mentioned above, such as roasted bean temperature signals. As an example, the bean temperature determined by the roasted bean temperature sensor can be assumed to be a predetermined characteristic value according to the selected roasting curve can be used as a characteristic event. When a characteristic event occurs, the control unit can be configured to modify or change the generation of the control output signal, or one or more of its components. As an example, the roasted bean temperature, the rear wall temperature, the drum air temperature, the set value of the heating power of the air heater, and / or the set value of the positive pressure device and / or the negative pressure device (such as the speed of the intake fan and / or the extractor fan) can be modified when a characteristic event occurs.

[0114] However, not all sensor signals are used directly for controlling the roasting process. Specific sensor signals may be used for supervising and monitoring the roasting process without influencing the control output signal. As an example, an air humidity signal generated by an optional air humidity sensor may be evaluated by the control unit in order to supervise the progress of the coffee bean roasting process in general and in particular the progress of the roasting process itself. Additionally, the air humidity is an indicator of the taste that can be expected from the roasted coffee beans. Furthermore, an exhaust gas temperature sensor may optionally be arranged to measure the exhaust gas temperature, for example at or in a chimney. The control unit may evaluate the exhaust gas temperature signal, typically for safety purposes.

[0115] The control output signal may include one or more control signals, via which the temperature conditions inside the drum, in particular the rear wall temperature, the drum air temperature and / or the bean temperature, can be influenced by controlling the operation of one or more of the air heater, the drum heater, the positive pressure device and the negative pressure device. Typically, an increase in the heating power of the drum heater and / or the air heater results in an increase in the temperature inside the drum, and vice versa. Similarly, an increased operation of the positive pressure device (in particular an increased rotational speed of the intake fan) will result in an increase in the temperature inside the drum, and vice versa. An increased operation of the negative pressure device (in particular an increased operation of the extractor fan) will result in a decrease in the temperature inside the drum, and vice versa. As previously mentioned, the airflow of hot air fed or entering the drum should generally correspond to the airflow of exhaust air extracted from or leaving the drum during roasting.

[0116] In a typical embodiment, the rear wall temperature can be controlled in a range from ambient temperature up to about 300 degrees Celsius, the temperature of the hot air can be controlled in a range from ambient temperature up to about 550 degrees Celsius, and the rotational speed of the drum rotor can be controlled if started, for example, in a range from 50 RPM (revolutions per minute) to 90 RPM, and the extractor fan and intake fan can be controlled for an air flow rate in a range of, for example, 10 liters per minute up to 350 liters per minute.

[0117] As explained above, controlling the execution of the cooling process via the cooling unit may be a closed-loop control, wherein at least one of the corresponding control signals, in particular the cooling rotor drive control signal, the cooling air supply device control signal and / or the cooling water supply device control signal, is generated or modified substantially in real time based on control input signals, in particular signals provided by one or more cooling sensors as feedback signals, and the selected roasting profile. In an alternative embodiment, the control signals as mentioned above are at least partially generated according to an open-loop control during cooling. In particular, while the supply device of cooling water is advantageously stopped at the moistening temperature threshold as explained above, the cooling air supply device, in particular the air intake fan, may be time-controlled or continue to operate until it is manually switched off and / or the next batch of coffee beans is to be roasted.

[0118] In some embodiments, the control unit may be configured to further modify or alter the generation of the control output signal in dependence on the control input signal when one or more limit events occur. Such limit events may be, for example, a roasted bean temperature, a hot air temperature inside the drum or an exhaust gas temperature that takes or exceeds a corresponding limit temperature. In such a case, the control unit may, for example, be configured to reduce the heating power of the drum heater, the amount of hot air provided via the positive pressure device and / or the heating power of the hot air supply device. The limit values, in particular the limit temperatures, may be fixed and / or may be part of the roasting curve.

[0119] The control algorithm and / or control parameters for generating the control output signal in dependence on the control input signal may be permanently stored by the control unit. Alternatively or additionally, the control unit may be configured to receive the control algorithm and / or control parameters for a single or multiple baking processes from a remote computer system to store the control algorithm and / or control parameters and to generate the control output signal according to the stored control algorithm and / or control parameters. In such an embodiment, the control algorithm and / or control parameters may be modified via the remote computer system when necessary.

[0120] According to an advantageous embodiment, a coffee roaster, and in particular a coffee roaster according to the present disclosure, may have a modular design and include a coffee roaster frame or base, which may, for example, include a control unit and potential supplementary devices, such as a power supply. The roasting unit, the cooling unit and the exhaust gas treatment unit may be designed as generally independent units, for example, plug-in units designed to be mounted on or inserted into a frame or base, wherein the base or frame and the individual modules advantageously include corresponding electrical couplers and fluid couplers, wherein the modules are coupled via the base or frame. However, some or all couplings (in particular fluid couplings) may also be directly between the modules. Optionally, some or all modules may be split into submodules, which are designed to be mounted individually on or inserted into a frame or base. In particular, a drum with a drum heater and a hot air supply device may be provided as a separate submodule. Similarly, an inlet module, a dregs separator module, which may include a hopper and a drum inlet baffle as mentioned above, may be provided and mounted on or inserted into a frame or base. In some embodiments, the control unit and / or the supplementary further devices as mentioned above are not included in the coffee roaster frame or base, but are also designed as independent modules. In addition, as further explained below in the context of exemplary embodiments, the combination of bean scale, bean tray and drawer can be provided as a separate and structurally different unit.

[0121] Such a modular design significantly simplifies the maintenance and cleaning of the coffee roaster, especially by a user or non-technical person. In addition, it simplifies the repair and exchange of defective modules.

[0122] In an embodiment, the control unit is configured to be operatively coupled to a remote computer system and to receive a selected roasting curve from the remote computer system. The remote computer system may be a centralized and / or cloud-based remote computing system. Advantageously, the remote computing system and the coffee roaster or its control unit are configured to communicate via the Internet, as explained above. In addition, in such an embodiment, the user interface device and the remote computer device as mentioned above may be configured to communicate via the Internet. In such an embodiment, the user interface device typically communicates with the coffee roaster via the remote computer system as an intermediate element. However, alternatively or additionally, the user interface device and the coffee roaster may be configured for direct wired and / or wireless communication. This is particularly advantageous for providing, for example, a start command for a roasting process to the coffee roaster, and for displaying information such as alarms and warnings to the user and information about the roasting process, such as sensor signals.

[0123] The coffee roasting system according to the present disclosure comprises a coffee roaster, wherein the control unit is configured for being operatively coupled to a remote computer as explained above. The coffee roasting system may also comprise a plurality of such coffee roasting machines. The coffee roasting system further comprises a remote computer system, wherein the remote computer system is configured to store a plurality of available roasting curves, and receive a user input for selecting a selected roasting curve from the plurality of available roasting curves, and transmit the selected roasting curve to the control unit. In such an embodiment, as explained above, the user typically selects the roasting curve on a user interface device, wherein the selection is transmitted to the remote computer device.

[0124] In some embodiments where the control unit is configured for operative coupling with a remote computer system, the control unit is configured to acquire sensor data during the coffee bean roasting process and transmit the acquired sensor data and / or data derived from the acquired sensor data to the remote computer system.

[0125] As explained above, the acquired data may specifically include one or more of a roasted bean temperature signal, a roasted bean temperature signal, a cooled bean temperature signal, a cooled bean color signal, a rear wall temperature signal, a drum air temperature signal, an inlet air temperature signal, an air humidity signal, an air flow signal, a crack detection signal and / or a water temperature sensor signal. In addition, the acquired sensor data may include green bean weight, roasted bean weight and / or a ratio or difference therebetween.

[0126] Additionally, the control unit may be configured to transmit the control output signal and / or data derived from the control output signal to a remote computer system.

[0127] The data derived from the acquired sensor data may be, for example, average values, extreme values, smoothed or filtered values, and characteristic durations or time points, such as the time from the start of the coffee bean roasting process to the time when the crack detection sensor detects the first crack, the roasted bean temperature at the end of the roasting process (before cooling), the cooled bean temperature at the end of the cooling process, the roasted bean color at the end of the roasting process (before cooling), the cooled bean color at the end of the cooling process, and the like.

[0128] The remote computer system may be configured to store and / or further evaluate and / or process data received from one or more coffee roasters, in particular for quality control purposes.

[0129] Furthermore, in an embodiment, the remote computer system is configured to evaluate the acquired sensor data and / or data derived from the acquired sensors to determine whether the coffee bean roasting process has been successful, and to transmit corresponding feedback information to the coffee roaster, in particular its control unit and / or user interface device.

[0130] In addition, the control unit and the user interface or user interface device can be configured to display specific characteristic events or milestones on the display of the user interface or user interface device, in particular characteristic events of the coffee bean roasting process. Such characteristic events may include one or more pre-roasting conditions being met or pre-heating being completed, the start of the roasting process, the first crack appearing, the end of roasting, the start of cooling and the end of cooling, or one or more of the conditions for the end of cooling being met. In addition, the control unit and the user interface or user interface device can be configured to display sensor data in real time on the display of the user interface or user interface device. BRIEF DESCRIPTION OF THE DRAWINGS

[0131] Figure 1 An exemplary embodiment of a coffee roaster according to the present disclosure is shown in schematic side view;

[0132] Figure 2 Shown as Figure 1 Arrangement of sensors in a coffee roaster as shown in FIG.

[0133] Figure 3 Shown as Figure 1 The control arrangement of the coffee roaster shown in FIG.

[0134] Figure 4 An embodiment of a coffee roasting system according to the present disclosure is shown;

[0135] Figure 5 The diagram shows the coffee bean roasting process;

[0136] Figure 6 A further exemplary embodiment of a coffee roaster according to the present disclosure is shown in schematic side view;

[0137] Figure 7 An additional exemplary coffee bean roasting process is illustrated. DETAILED DESCRIPTION

[0138] In the following, we first refer to Figure 1 , which shows an exemplary embodiment of a coffee roaster 1 according to the present disclosure in a schematic side view. The coffee roaster 1 includes a roasting unit 11, a cooling unit 14, and an exhaust gas treatment unit 15. In addition, the coffee roaster 1 includes a structurally independent or removable bean tray 17, which has a drawer 18 and an integrated bean scale 16.

[0139] The roasting unit 11 comprises a drum 111 having a drum body 1111 and a front wall 1112 which in combination create a generally cylindrical or disc-shaped overall shape of the drum 111. Advantageously, the drum 111 has a filling volume or inner drum space suitable for roasting approximately 1 kg of coffee beans. The drum has a horizontal drum axis A which coincides with the rotor axis of a rotor drum 112 rotatably arranged inside the drum 111. The drum is designed as explained in the general description, wherein the front wall 1112 is transparent and removable. The rear wall 11111 of the drum body 1111 is designed as a sandwich to facilitate its thermal properties as explained above and is thermally coupled to an exemplary resistive drum heater 116 arranged outside the drum 111. The drum heater 116 is arranged to ensure a substantially uniform heating of the rear wall 11111. In the upper region of the rear wall 11111, a drum inlet 11112 is arranged. Similarly, a drum outlet 11113 is arranged in the lower region of the rear wall 11111. The drum rotor 112 is connected to a drum rotor drive 113, which is realized as an electric motor and is arranged outside the drum.

[0140] A hot air supply device 114 is provided to supply hot air into the drum 111. It is usually arranged outside the drum and is fluidly connected to the drum outlet 11113 via a duct (not shown) to supply hot air into the drum. In the illustrated embodiment, the hot air supply device 114 includes a resistive air heater 1141 and a positive pressure supply device 1142 in the form of an intake fan. In the illustrated embodiment, the hot air supply device 114 is fluidly coupled to the drum outlet 1113 via a duct, wherein the drum outlet 1113 is simultaneously used as a hot air inlet. However, this is not necessary, and alternatively, a separate hot air supply device opening can be foreseen in the drum body 1111, particularly in the rear wall 11111.

[0141] Via corresponding pipes, the drum inlet 1112 is connected to a hopper 1113, into which the green beans to be roasted are filled. In the connection of the drum 111 or its interior space with the hopper 1111, a drum inlet baffle is arranged. Only when the drum inlet baffle 1114 is open can the green beans present in the hopper 1113 be transferred to the interior space of the drum 111 by means of gravity. The drum inlet baffle is usually opened only for filling the drum 111 with green coffee beans and is closed in other cases. In order to fill the drum with green coffee beans, in this embodiment, such beans are first filled by the user into a bean tray 17, wherein the weight of the green beans is automatically measured by a bean scale 16. Subsequently, the user moves or lifts the bean tray 17 to the hopper 1113 with a drawer 18 and a bean scale 16, and fills the beans from the bean tray 17 into the hopper 1113.

[0142] In this embodiment, the bean tray 17, the drawer 18 and the bean scale 16 form an integral unit which is structurally separate from the further components and units of the coffee roaster 1 and which is removable by a user.

[0143] In addition, an exhaust gas extractor 115 is provided to remove exhaust gases from the interior of the drum. The exhaust gas extractor 115 comprises a negative pressure device 1151, which is fluidically coupled to the exhaust gas extraction opening 11114 in the upper area of ​​the rear wall 11111 via a corresponding duct, and in this embodiment, is an exhaust gas treatment unit 15, as further explained below. In this design, the negative pressure device 115 comprises an extractor fan 1151 to generate a suction pressure. In addition, the exhaust gas extractor 1152 comprises a chimney 1152 fluidically coupled to the extractor fan 1151. In the exhaust gas extraction opening 11114, a bean holder 11115 in the form of a porous plate or a grid is arranged to prevent coffee beans from leaving the inner space of the drum 111 while allowing air and dregs to pass through.

[0144] The exhaust gas treatment unit 15 is fluidly arranged between the exhaust gas outlet 1114 of the drum 111 and the negative pressure device or extractor fan 1151 with the chimney 1152. Due to the exhaust gas treatment unit, the exhaust gas finally leaving the chimney 1152 is cold and substantially free of undesirable odorous substances, thereby allowing the coffee roaster 1 to be used in a normally closed room.

[0145] In the shown design, a chaff separator unit 19 is fluidly arranged between the drum 111 and the exhaust gas treatment unit 15. According to the general description above, the chaff separator unit 19 may in particular comprise a cyclone separator and / or a mechanical chaff retaining filter.

[0146] The main element of the exhaust gas treatment unit 15 is a water tank 151. In operation, the water tank 151 is filled with water to a filling level F, wherein the filling level F is below the exhaust gas extraction opening 11114 of the drum 11. In the embodiment shown, the water tank 151 is fluidly coupled to a clean water supply device 152 via a clean water supply valve 1521 for supplying clean water to the water tank 151 when the clean water supply valve 1521 is open. In addition, in this embodiment, the water tank 151 is fluidly coupled to a waste water discharge device 151 via a waste water discharge valve 1531 for removing waste water from the water tank 151 when the waste water discharge valve 1531 is open.

[0147] Typically, the filling volume of the water tank 151 may be in a typical range of 0.5 to 2 liters, for example one liter, and is advantageously sized to be sufficient to allow for the treatment of exhaust gases for a number of, for example, one to three baking operations. Note that in principle, explicit fresh water supply 152 and waste water discharge 153 and corresponding fresh water supply valve 1521 and waste water discharge valve 1531 may be omitted. In such an embodiment, the water tank 151 may be filled and emptied manually by the user.

[0148] Below the filling level F, a water tank air inlet 1511 is arranged, which is fluid-cooled via a duct with exhaust air extraction openings 1114 and the corresponding inner drum space.

[0149] Above the filling level F, the tank air outlet 1512 couples the interior of the tank 151 via a duct, via a condenser 155 and an exhaust air filter 154, with a negative pressure device or extractor fan 1151, so that the air leaving the tank 151 first passes through the condenser 155 and then through the exhaust air filter 154, which is typically an activated carbon filter, before leaving the chimney 1152. Apart from the tank air inlet 1511 and the tank air outlet 1512, the tank 151 is usually closed during operation.

[0150] Inside the water tank 115 and usually below the filling level F, an air bubble intensifier r156 in the form of a perforated plate is arranged, which extends substantially over the entire side area of ​​the water tank 151. In embodiments without a dedicated dregs separator unit, the air bubble intensifier 156 can simultaneously serve as a dregs separator, as explained above in the general description.

[0151] During the roasting process, the negative pressure device or extractor fan 1151 is usually active, thereby generating a negative pressure or underpressure in the air volume inside the water tank 115 above the filling level F, causing the water inside the water tank 151 to be agitated and bubbles to be generated. The exhaust gases entering the water tank 151 together with the dregs come into contact with the water and are thus cooled, freed from the dregs and at least partially freed from odorous substances and associated materials contained otherwise, in particular fumes. The exhaust gases rise to the water surface at the filling level F and, after passing through the condenser 155 and the exhaust gas filter 154, are extracted by the negative pressure device or extractor fan 1151, as explained above.

[0152] In order to cool the roasted coffee beans at the end of the roasting process, a cooling unit 14 is present in this embodiment. The cooling unit 14 comprises a cooling container 141 having a cooling container inlet 1411 and a cooling container opening 1412. The cooling container inlet 1411 is advantageously arranged below the bean outlet opening 1113 of the drum 111, thereby allowing the roasted coffee beans to be transferred from the inner space of the drum into the cooling container 141 by means of gravity. Between the drum outlet 1113 and the cooling container inlet 1411 or at the connection thereof, there is a drum outlet damper 1115, which only allows the coffee beans to be transferred into the cooling container 141 in its open state. During the roasting of the coffee beans in the drum 111, the drum outlet damper 1115 is closed and is only opened at the end of roasting.

[0153] The cooling unit 14 optionally comprises a rotatably arranged cooling rotor 142, which is arranged inside the cooling container 141 and is operatively coupled to a cooling rotor drive 143 in the form of an electric motor. In the embodiment shown, cooling of the coffee beans is obtained by means of cold air and optionally a mist of water droplets, thereby allowing effective cooling in a short time without wetting the coffee beans or otherwise adversely affecting the coffee beans.

[0154] To provide cool air, a cooling air supply 144 in the form of a cooling fan 144 is provided, which aspires or draws cool air from the environment, which is fed into the cooling container 141 and moves between and along the coffee beans. Advantageously, the cool air enters the cooling container 141 at its bottom side.

[0155] In order to provide cooling water, an optional cooling water supply device 145 is provided, which includes a nozzle arrangement and a nozzle control valve. Via the nozzle arrangement, small water droplets or mist are generated in the cooling container 141. Via the cooling rotor that rotates during cooling, the coffee beans are continuously moved and exposed to cold air and optional water droplets. At the end of the cooling process, the cooling container outlet baffle 146 opens, thereby allowing the cooled coffee beans to be transferred to the bean tray 17 placed below the cooling container outlet 1412 by gravity. During cooling, the cooling container outlet baffle is closed and is only opened at the end of cooling. During the transfer of coffee beans from the cooling container 114 to the bean tray 17, the cooling rotor 141 advantageously rotates to ensure that the coffee beans are actually transferred to the cooling container outlet 1412 and leave the cooling container 141.

[0156] In the following, additional reference is made to Figure 2 , Figure 2An exemplary embodiment of an arrangement of various sensors of a sensor arrangement of a coffee roaster 1 is illustrated. The sensors are used to control and monitor the coffee bean roasting process, in particular the roasting and cooling of the coffee beans, and the operation of the exhaust gas treatment unit 15.

[0157] In the drum 11, a roasted bean temperature sensor 12a, a roasted bean color sensor 12b, a rear wall temperature sensor 12c, a drum air temperature sensor 12d and a crack detection sensor 12e are arranged respectively, which can be exemplarily realized as a loudspeaker. Similar to the drum heater 116, all these sensors are arranged at the drum body 1111 and are advantageously arranged at and / or in the rear wall 11111 to allow a simple removal of the front wall 1112. As explained above, in this embodiment, at the drum outlet 11113, which also serves as a hot air supply device opening into the drum 111, an inlet air temperature sensor 12f is arranged. In the water tank 115 and below the filling level F, 15, a water temperature sensor 12j is arranged.

[0158] Additionally, in this embodiment, an optional exhaust gas temperature sensor 12k is arranged downstream of the negative pressure device or extractor fan 1151, which measures the air temperature of the exhaust gas before it leaves the chimney 1152. Between the drum outlet 1113 and the water tank air inlet 1511, an optional air outlet pressure sensor 12h, an air inlet pressure sensor 12h2 and an optional air humidity sensor 12g are arranged, which measure the exhaust gas pressure and exhaust gas humidity, respectively.

[0159] In order to monitor the cooling of the coffee beans and detect whether the cooling end condition is met, in this embodiment, a cooling bean temperature sensor 12i is arranged inside the cooling container 141. As mentioned above, a cooling bean color sensor may additionally or alternatively be present.

[0160] In the following, additional reference is made to Figure 3, which shows a control arrangement of a coffee roaster 1 in a schematic functional view. The coffee roaster 1 comprises a control unit 13, which is typically based on one or more microcomputers and / or microcontrollers running corresponding software codes, but may also include further electronics and circuit systems. The control unit 13 may further comprise a sensor interface and / or evaluation circuit system for some or all of the various sensors explained above and further below. However, such a sensor interface and / or evaluation circuit system may also be part of some or all of the sensors and be integrated therewith. Similarly, the control unit 13 may comprise drive and / or control circuit systems for various motors and further actuators as well as rear wall heaters and air heaters and further actuators for valves and shutters. However, such a drive and / or circuit system may also be part of some or all of these units or components and be integrated therewith. Typically, the control unit 13 is configured to evaluate sensor signals and to control and monitor the operation of the coffee roaster 1 as a whole, in particular the roasting unit 11, the cooling unit 14 and the exhaust gas treatment unit 15.

[0161] The control unit 13 comprises a memory storing the necessary program code (not separately referenced) which, when executed, instructs a further microcomputer and / or microcontroller of the control unit 13 to control the operation of the coffee roaster 1. In addition, the control unit 13 comprises a memory for storing a selected roasting profile and optionally a plurality of available roasting profiles. In addition, the control unit 13 further advantageously comprises a memory for at least temporarily storing sensor data acquired by the sensors and the optional bean scale 16 during or in the context of one or more coffee bean roasting processes, as explained above in the general description.

[0162] In the illustrated embodiment, the control unit 13 receives input signals or sensor signals from a roasted bean temperature sensor 12a, a roasted bean color sensor 12b, a rear wall temperature sensor 12c, a drum air temperature sensor 12d, a crack detection sensor or microphone 12e, an inlet air temperature sensor 12f, an air humidity sensor 12g, an air outlet pressure sensor 12h, an air inlet pressure sensor 12h2, a cooling bean temperature sensor 12i, a water temperature sensor 12j, an exhaust temperature sensor 12k and a fill level sensor or float gauge 12l and a bean scale 16. The sensors are operatively coupled to the control unit 13 in a hardwired and / or wireless manner. While most sensors are typically hardwired, in particular the bean scale 16 may advantageously be wirelessly coupled to the control unit 16, for example via Bluetooth or WLAN. The sensor signals, in particular those associated with the roasting and cooling of the coffee beans, are combined to form control input signals as explained above.

[0163] In the embodiment shown, the control unit 13 generates control signals for the air heater 1141, the positive pressure device or intake fan 1142, the negative pressure device or extractor fan 1151, the drum heater 116, the drum rotor drive 113, the cooling rotor drive 143, the cooling air supply device or cooling fan 1144 and the cooling water supply device 145 or its nozzle valve. In addition, the control unit generates control signals for the drum inlet baffle 1114, the drum outlet baffle 1115, the cooling container outlet baffle 146 and the fresh water supply valve 1521 and the waste water discharge valve 1531. The different control signals can be analog signals and / or binary signals. The control signals (especially those associated with the roasting and cooling of the coffee beans) are combined to form the control output signals as explained above.

[0164] In the following, reference is made to Figure 4 , a coffee roasting system according to the present disclosure is shown. The coffee roasting system includes a plurality of coffee roasters 1a, 1b, 1c, 1d according to the present disclosure and a remote computer system 2. Exemplarily, four coffee roasters are shown for illustrative purposes, but other numbers (including only one) of coffee roasters may also be present. The coffee roasters 1a, 1b, 1c, 1d may be, for example, coffee roasters 1 or 1′ as discussed above and further below.

[0165] The coffee roasters 1a, 1b, 1c, 1d are operatively coupled to a remote computer system 2, which is exemplarily shown as a centralized computer system, but may also be a distributed, in particular cloud-based, computer system.

[0166] The coffee roasters 1a, 1b, 1c, 1d and a remote computer system 2 are operatively coupled, exemplarily via an Internet-based connection.

[0167] In addition, there are a plurality of user interface devices 3a, 3b, which are exemplarily separate and distinct from the coffee roasters 1a, 1b, 1c, 1d, and are implemented, for example, as tablet computers. In the illustrated configuration, the user interface device 1a is operatively coupled to two coffee roasters 1a, 1b, while the other two coffee roasters 1c, 1d are each operatively coupled to a user interface device 3b or 3c in a one-to-one relationship. In this configuration, the coffee roasters 1a, 1b may be located close to each other, for example in one store, while the coffee roasters 1c, 1d are located at different locations in another store.

[0168] In the illustrated configuration, the user interface device communicates directly with the coffee roaster, for example via Bluetooth, and may communicate with the remote computer device 2 via the coffee roaster. However, in an alternative configuration, the user interface devices 3a, 3b, 3c are connected to the Internet and communicate with the coffee roasters 1a, 1b, 1c, 1d and / or the remote computer device 2 via the Internet. In a further configuration, the user interface devices 3a, 3b, 3c and the coffee roasters 1a, 1b, ac, 1d communicate only with the remote computer device 2. As a central example, the user interface device and the coffee roaster communicate via the remote computer device.

[0169] In particular, if the user interface devices 3a, 3b, 3c are general purpose devices, they may store corresponding program codes, in particular suitable software applications or apps. However, alternatively or additionally, the control unit 13 of each coffee roaster 1 and / or the remote computer system 2 also comprises an implemented web server configured to generate and provide web pages, which are transmitted to and processed by the user interface devices.

[0170] In the following, additional reference is made to Figure 5 , Figure 5 Examples of roasting coffee beans and examples of selected roast profiles and / or target roast profiles are shown.

[0171] exist Figure 5 In the graph of FIG. 1 , the vertical axis (ordinate) shows the temperature inside the drum (as measured by the drum air temperature sensor 12a, the rear wall temperature sensor 12c and / or the roasted bean temperature sensor 12d) as a function of time.

[0172] At the start of the coffee bean roasting process, the control unit 13 generates a pre-roasting control output signal, thereby heating the drum, and in particular the inner drum space, until the selected pre-roasting conditions are met. During pre-heating, the hot air supply device 114 (in particular, the positive pressure device or the air intake fan 1142 and the air heater 1141, the drum heater 116) and the exhaust air extractor 115 (in particular, the negative pressure device or the extractor fan 1151) operate. In addition, the drum rotor drive 113 can be optionally activated to ensure that the hot air is evenly distributed inside the inner drum space. During pre-heating, the dampers and in particular the drum inlet damper 1114 and the drum outlet damper 11115 are controlled by the control unit 13 to be closed. During pre-heating, the user can fill the bean tray 17 with coffee beans, which are weighed by the bean scale 16 and the weight is transmitted to the control unit 13 as the green bean weight. Subsequently, the user fills the green coffee beans from the bean tray 17 into the hopper 1113, and they remain in the hopper as long as the drum inlet damper 1114 remains closed.

[0173] The pre-roasting condition is characterized by the pre-heating temperature. When the control unit 13 determines that the pre-roasting condition is met, the drum inlet damper 1114 is controlled to be temporarily opened, thereby allowing the green beans to be transferred or dropped into the drum 111, and the drum inlet damper is controlled to be closed again. During the transfer of the green coffee beans into the drum 111, the drum rotor drive 113 is advantageously controlled to rotate the drum rotor 112 at an appropriate speed to ensure that the green coffee beans are transported away from the drum inlet 1112.

[0174] As coffee beans are filled into the drum 111, the temperature of the inner drum space decreases until a turning point temperature is reached at the turning point, which is part of the selected roasting curve. However, when the actual temperature decreases, the control output signal is controlled to maintain the preheating temperature. After the turning point, the temperature increases again until the crack detection sensor or the loudspeaker 112e detects the first crack. In the subsequent development stage, the control temperature is slowly increased until the target roasted bean temperature and the target roasted bean color according to the selected roasting curve are reached, as indicated by the roasted bean temperature sensor signal and the roasted bean color signal. The target roasted bean temperature and the target roasted bean color reached indicate the roasting end condition.

[0175] During baking, the temperature is controlled by appropriately controlling the air heater 114, in particular the hot air supply 1141 and the positive pressure or intake fan 1142, the drum rotor drive 113, the drum heater 116 and the negative pressure or extractor fan 1151, via control output signals as generated by the control unit 13. Although in principle all of these units or elements may be controlled in a time-varying manner, some may also be controlled in a substantially stable manner and / or in an on / off manner.

[0176] When the roasting end condition is met, the control unit 13 controls the drum outlet damper 1115 to be opened, thereby transferring the coffee beans from the drum 111 to the cooling container 141 of the cooling unit 14. During this transfer, the drum rotor drive 113 and the cooling rotor drive 143 are advantageously controlled to operate the drum rotor 112 and the cooling rotor 141 at appropriate speeds to ensure that substantially all the coffee beans are transferred to the cooling container 141. In the case where the roasting end condition is met, the hot air supply device 114 having the air heater 1141 and the positive pressure device or the intake fan 1142, and the negative pressure device / extractor fan 1151 can be deactivated.

[0177] During cooling, the cooling rotor drive 143 is activated to rotate the cooling rotor 142, and the cooling air supply or cooling fan 144 and the nozzle valve of the cooling water supply 145 are controlled by the control unit 13 to cool the beans until a target cooled bean temperature as part of the selected roasting profile is reached, thereby indicating an end of cooling condition. During cooling, the temperature of the beans is measured by the cooled bean temperature sensor 12i.

[0178] When the cooling end condition is met, the control unit 13 controls the cooling container outlet baffle to be opened, thereby transferring the cooled coffee beans to the bean tray 17 placed below the cooling container outlet 146.

[0179] Optionally, a tray sensor 12m, for example in the form of an optical, capacitive or inductive sensor or switch, is arranged at the cooling unit outlet 1412 and operatively coupled to the control unit 13. The control unit 13 can be configured to open the cooling container outlet shutter 146 only if the tray 17 is actually present and correctly positioned. Similarly, a drawer sensor 12n may be present to ensure that the drawer 18 is inserted when the cooling container outlet shutter 146 is opened.

[0180] The weight of the roasted coffee beans is weighed by the bean scale 16, and the weight is transmitted as the weight of the roasted beans to the control unit 13. Finally, the user can pull the drawer 18 and remove the roasted and cooled coffee beans.

[0181] In the following, we first refer to Figure 6 , similar to Figure 1 , Figure 6 An exemplary embodiment of a coffee roaster 1 ' according to the present disclosure is shown in a schematic side view. Since the coffee roaster 1 ' is similar to the coffee roaster 1 in its basic design and operation and in many aspects regarding the design of the device, the following description focuses on the differences. Note that for the sake of clarity, various sensors, actuators and / or other components are not all shown in this embodiment. In principle, there can be as follows Figure 2 The coffee roaster 1 ' has different designs, in particular with regard to the cooling and further processing of the roasted coffee beans, and the exhaust gas treatment.

[0182] In such Figure 6 In the embodiment illustrated in FIG. 1 , a user-removable cooling container 141 ' is foreseen, which also serves as a bean tray for removing roasted coffee beans from the coffee roaster 1 '. The cooling container 141 ' is configured to rest on a bean scale 16. The cooling container 141 ' has a perforated bottom that allows air to pass through, however the perforations are designed so that beans cannot pass through.

[0183] To cool the roasted coffee beans, Figure 1 , Figure 2 1 ', a cooling air supply trim or cooling fan 144 is foreseen. However, for the coffee roaster 1 ', only air is used for cooling. During cooling, the cooling air supplied by the cooling fan 144 passes through and thereby cools the coffee beans, and leaves the cooling container into the drum via the drum outlet 11113. The cooling air is removed or extracted from the drum 111 by a negative pressure device or extractor fan 1151. In this embodiment, the exhaust extractor serves a dual purpose of extracting both the exhaust gases from the roasting and the cooling air.

[0184] In an embodiment, the cyclone separator, catalyst and / or exhaust gas heater are operated during the cooling period so that the exhaust gas is treated.

[0185] The completion of cooling or the satisfaction of the cooling end condition can be determined in the same manner as in the previously discussed embodiments and / or according to the general description. In a particular design, there is no dedicated cooling container outlet damper under the control of the control unit. Therefore, the control unit can optionally provide a user indication, particularly a visual and / or audible indication, when the cooling end condition is satisfied.

[0186] The grounds separator 19' of the coffee roaster 1' comprises: a cyclone separator 191' for separating grounds from the exhaust gas flow. The cyclone separator 191' can be controlled by a control unit and activated during the roasting process. After leaving the drum outlet 11114, the exhaust gases are fed into the cyclone separator 191', in which the grounds are usually separated and moved to a grounds drawer 192' for subsequent treatment. From the cyclone separator 191', the exhaust gases are fed to a particle filter, which is exemplarily realized as an electrostatic particle filter 159'. Before entering the electrostatic particle filter 158', the exhaust gases pass through a grounds retaining filter 193', which filter 193' can be realized as a mechanical filter, for example as a porous plate, and prevents any residual grounds that may have passed through the cyclone separator 191 from entering further downstream components.

[0187] The dregs separator 191' has additionally attached a fire extinguisher 194', which is configured to extinguish a fire in the dregs separator 191' and / or the dregs drawer 192'. The fire extinguisher 194' is connected to the control unit 13, which controls its activation based on the control unit 13 detecting a condition indicative of a fire. The condition indicative of a fire can be determined using a fire detector. For example, a fire can be detected based on a temperature measured by an additional fire temperature sensor, a smoke detector or any other type of fire detector arranged in the fire extinguisher 194' itself, in the dregs separator 191', in the dregs drawer 192', or downstream of the dregs separator 191'.

[0188] The exhaust gas treatment unit 15' of the coffee roaster 1' comprises a catalyst 157b' for removing odorous, harmful, toxic and / or polluting substances, such as carbon monoxide. In order to ensure an appropriate temperature of the exhaust gases for the catalyst 157b' to operate effectively, an exhaust gas heater 157a' is arranged upstream of the catalyst 157b'. Downstream of the catalyst 157b', an exhaust gas cooler 157c' is arranged to cool the substantially hot exhaust gases leaving the catalyst 157b'. The catalyst may comprise a catalytic converter known from vehicle exhaust systems.

[0189] In operation, the exhaust gas heater 157a' is advantageously not operated continuously, but only in one phase, in particular in the later phases of the roasting process as further explained below, when most odors appear. Otherwise, odorous particles or substances are retained by the electrostatic particle filter 158'. The operation of the exhaust gas heater 157a' is controlled by the control unit of the coffee roaster. Typical heating temperatures may be, for example, in the range of 200° C. to 400° C., in particular 250° C. to 300° C., depending on the type and specific characteristics of the catalyst 157b'.

[0190] As explained previously, from the exhaust gas cooler 157c', which is a downstream element of the exhaust gas treatment unit 15', the exhaust gas passes through the condenser / dehumidifier 155 and the exhaust gas extractor 115 and leaves the coffee roaster 1' via the chimney 1152.

[0191] As explained previously, in the design shown, the cooling air follows the same route as the exhaust air during baking.

[0192] In the following, additional reference is made to Figure 7 , roughly similar to Figure 5 , Figure 7 Further examples of roasting coffee beans and examples of selected roasting curves and / or target roasting curves are shown. The examples shown use a method based on Figure 6 The coffee roaster 1' shown in FIG. 1 is of this form. Because the roasting process is usually carried out in a manner similar to Figure 5The process of roasting the bean temperature is similar, so the following description focuses on specific aspects of this embodiment.

[0193] exist Figure 7 In FIG. 1 , the thick line schematically shows the roasted bean temperature or roasted bean temperature signal determined by the roasted bean temperature sensor 12 a, which generally corresponds to or indicates the desired roasted bean temperature according to the selected roasting curve. The dotted line is the temperature of the rear wall 11111 of the drum 111. In addition, Figure 7 The supply air flow is shown as a dashed line.

[0194] In the preparation phase O, the weight of the coffee beans is determined by a bean scale 16, as explained previously. Here, a cooling container 141' serves as a bean tray. Phase I is a preheating phase, in which the rear wall 11111 and the air inside the drum 111 are heated to a desired target value according to the selected roasting profile. In the example shown, the rear wall temperature is kept substantially constant, however, this may not be the case for another selected roasting profile. The preheating phase I is here two-part and comprises the preheating phase itself 1-1, in which, in particular, the drum air temperature is heated to a desired value according to the selected roasting profile. When this temperature is reached, indicated by a dot as event E1, the drum air temperature is controlled to remain substantially constant or stable in a preheating holding phase I-1. At the end of the preheating holding phase, the control unit controls the drum inlet damper 1114 to be temporarily opened, thereby transferring the coffee beans filled into the hopper 1113 by the user after the weight has been determined into the drum 111. In the example shown, the course of the roasted bean temperature during roasting is similar to that discussed previously. Figure 5 In this example, the drum rotor drive 113 is controlled to rotate the drum rotor 112 at a constant rotational speed, however this is not mandatory. Alternatively, the selected roasting profile may include a time-varying profile.

[0195] In this example, both the positive pressure device or the air intake fan 1142 and the air heater 1141, which have the main influence on the drum air temperature, are controlled as follows: The air intake fan 1142 is controlled in multiple stages to a predetermined airflow and / or pressure after the air intake fan 1142 or at the entrance to the drum 111. The air heater 1141 is controlled so that the desired roasted bean temperature is achieved as a function of time. The different stages can be separated, or the switching between stages can be time controlled, occurring at a roasted bean temperature assuming a specific roasted bean temperature according to a selected roasting profile, and / or a roasted bean color assuming a specific roasted bean color according to a selected roasting profile.

[0196] As an example, at the end of phase 1-b, the intake fan 1142 is set to 60% of the maximum airflow rate and the temperature of the supply air is set to 450°C. As the relatively cold beans enter the drum 111, the temperature detected by the roasted bean temperature sensor 12a (as indicated by the solid line) drops. This causes the temperature indicated by the roasted bean temperature sensor 12a to drop rapidly until the temperature indicated by the roasted bean temperature sensor 12a matches the temperature of the beans (which has risen due to the hot supply air and the hot drum 111). During phase II, the control unit 13 is configured to detect the lowest temperature indicated by the roasted bean temperature sensor 12a. When the minimum value has been detected, the intake fan 1142 is adjusted to 65% of the maximum airflow rate and the temperature of the supply air is set to 460°C. Approximately from this point onwards, the temperature measured by the roasted bean temperature sensor 12a corresponds well to the actual temperature of the beans. Once the roasted bean temperature sensor 12a indicates that the beans have reached 193°C, point E2 is reached. The intake fan 1142 is then set to 40% of the maximum airflow rate and the temperature of the supply air is set to 430° C. The specific temperatures indicated in the described example depend on the baking profile.

[0197] The negative pressure device or extractor fan 1151 is controlled as explained above to ensure a stable and non-returned airflow. The airflow and / or pressure at the air inlet and / or exhaust air extraction opening 11114 can be further monitored for predefined thresholds. If exceeded, this can indicate a fault or defect, such as a clogged filter.

[0198] In the example shown, the roasting itself is two-part, with a first roasting phase II-1 and a subsequent second roasting phase II-2. In contrast to the first roasting phase II-1, the exhaust gas heater 157a' is activated to heat the exhaust gases to a temperature of, for example, 300°C, to allow the catalyst 157b' to eliminate odorous, harmful, toxic and / or polluting substances, as previously explained in the catalytic process. The start of the second roasting phase II-2 can be initiated, for example, depending on the roasted bean temperature, exemplarily at a value of 150°C.

[0199] The end of the baking condition (indicated as characteristic event E-3) is similar to Figure 5 , determined by the coffee bean temperature and optionally the coffee bean color assuming corresponding target values ​​defined by the selected roasting curve. In addition, the time of roasting can define the end of the roasting conditions, in particular the time of roasting at and / or above a specific temperature. However, taking into account the different design and operation of the cooling unit 15' compared to the cooling unit 15 and the manual removal of the roasted coffee beans from the cooling container 141', the subsequent steps of cooling III and determining the weight IV of the roasted coffee beans are performed as explained above.

[0200] Reference numerals

[0201] 1, 1′1a, 1b, 1c, 1d Coffee roaster

[0202] 11 Baking unit

[0203] 111 Roller

[0204] 1111 Drum body

[0205] 11111 Rear wall (drum body)

[0206] 11112 Drum entrance

[0207] 11113 Roller outlet

[0208] 11114 Exhaust extraction opening

[0209] 11115 Bean holder / perforated plate

[0210] 1112 Anterior wall

[0211] 1113 Hopper

[0212] 1114 Drum inlet baffle

[0213] 1115 Drum outlet baffle

[0214] 112 Drum rotor

[0215] 113 Drum rotor drive

[0216] 114 Hot air supply device

[0217] 1141 Air Heater

[0218] 1142 Positive pressure device / intake fan

[0219] 115 Exhaust gas extractor

[0220] 1151 Negative pressure device / extractor fan

[0221] 1152 Chimney

[0222] 116 Roller Heater

[0223] 12a Roasted Bean Temperature Sensor

[0224] 12b Roasted Bean Color Sensor

[0225] 12c Rear wall temperature sensor

[0226] 12d Drum air temperature sensor

[0227] 12e Crack Detection Sensor / Amplifier

[0228] 12f Intake air temperature sensor

[0229] 12g Air Humidity Sensor

[0230] 12h air outlet pressure sensor

[0231] 12h2 Air inlet pressure sensor

[0232] 12i Cooling Bean Temperature Sensor

[0233] 12j Water temperature sensor

[0234] 12k Exhaust Gas Temperature Sensor

[0235] 121 Fill level sensor / float gauge

[0236] 12m Pallet Sensor

[0237] 12n Drawer Sensor

[0238] 13 Control Unit

[0239] 14' Cooling Unit

[0240] 141, 141' cooling vessel

[0241] 1411 Cooling container inlet

[0242] 1412 Cooling container outlet

[0243] 142 Cooling rotor

[0244] 143 Cooling rotor drive

[0245] 144 Cooling air supply unit / cooling fan

[0246] 145 Cooling water supply device / nozzle layout

[0247] 146 Cooling container outlet baffle

[0248] 15, 15' exhaust gas treatment unit

[0249] 151 Water Tank

[0250] 1511 Water tank air inlet

[0251] 1512 Water tank air outlet

[0252] 152 Clean water supply device

[0253] 1521 Clean water supply valve

[0254] 153 Wastewater discharge device

[0255] 1531 Wastewater Discharge Valve

[0256] 154 Exhaust filter

[0257] 155 Condenser

[0258] 156 Bubble Enhancer / Dregs Separator

[0259] 157a' Exhaust gas heater

[0260] 157b' Catalyst

[0261] 157c' Exhaust Gas Cooler

[0262] 158' (Electrostatic) Particulate Filter

[0263] 16 Bean Scale

[0264] 17 Bean Tray

[0265] 18 Drawers

[0266] 19. Dregs separator

[0267] 191' Cyclone Separator

[0268] 192' Trash Drawer

[0269] 193' Dregs Retention Filter

[0270] 194' Fire Extinguisher

[0271] 2 Remote Computer Systems

[0272] 3a, 3b User interface device

[0273] F Fill level (tank)

[0274] A Drum axis

Claims

1. A coffee roaster (1) for performing a coffee bean roasting process, wherein the coffee roaster (1) comprises a) a baking unit (11), wherein the baking unit (11) comprises: - a drum (111), wherein the drum (111) comprises a drum body (1111) having a heat-conducting rear wall (11111) and having a drum inlet (11112) and a drum outlet (11113), and the drum further comprises a removable front wall (1112) for cleaning and maintenance purposes, - a drum rotor (112), wherein the drum rotor (112) is rotatably arranged inside the drum (111), - a drum rotor drive (113) operatively coupled to said drum rotor (112), - a hot air supply device (114), wherein the hot air supply device comprises an air heater (1141) and a positive pressure device (1142) for feeding hot air into the drum (111), - a drum heater (116), wherein the drum heater (116) is thermally coupled to the rear wall (11111), b) a sensor arrangement, wherein the sensor arrangement comprises a roasted bean temperature sensor (12a), wherein the roasted bean temperature sensor (12a) is configured to measure the roasted bean temperature of coffee beans located inside the drum (111) and provide a roasted bean temperature signal, c) a control unit (13) for controlling the execution of the coffee bean roasting process by the coffee roaster (1), wherein the control unit (13) is configured to receive a control input signal as a function of time, wherein the control input signal comprises the roasted bean temperature signal, wherein the control unit (13) is further configured to automatically generate a control output signal as a function of time in dependence on the control input signal, wherein the control output signal comprises a drum heater control signal, a drum rotor drive control signal and at least one of an air heater control signal and / or a positive pressure device control signal, thereby controlling the operation of at least one of the drum heater (116), the drum rotor drive (113), and the air heater (1141) and / or the positive pressure device (1142) to roast the coffee beans in the drum (111) according to a predetermined selected roasting curve, The selected roasting profile comprises a desired roasted bean temperature and a target roasted bean temperature as a function of time, wherein the control unit (13) is configured to determine whether a roasting end condition is met, wherein the roasting end condition comprises that the coffee beans inside the drum (111) have the target roasted bean temperature.

2. The coffee roaster (1) according to claim 1, wherein: The front wall (1112) is transparent.

3. The coffee roaster (1) according to any one of the preceding claims, wherein the sensor arrangement further comprises at least one of the following: - a roasted bean color sensor (12b), wherein the roasted bean color sensor (12b) is configured to measure the roasted bean color of coffee beans located inside the drum and provide a roasted bean color signal, wherein the control input signal comprises the roasted bean color signal, - a rear wall temperature sensor (12c), wherein the rear wall temperature sensor (12c) is configured to measure the rear wall temperature of the rear wall (11111) and provide a rear wall temperature signal, wherein the control input signal includes the rear wall temperature signal, a drum air temperature sensor (12d), wherein the drum air temperature sensor (12d) is configured to measure the drum air temperature inside the drum (111) and provide a drum air temperature signal, wherein the control input signal includes the drum air temperature signal, an inlet air temperature sensor (12f), wherein the inlet air temperature sensor (12f) is configured to measure the inlet air temperature of the hot air fed into the drum (111) and to provide an inlet air temperature signal, wherein the control input signal comprises the inlet air temperature signal, - an air humidity sensor (12g), wherein the air humidity sensor (12g) is configured to measure the extracted air humidity of the air extracted from the drum (111) and to provide an air humidity signal, wherein the control input signal comprises the air humidity signal, - an air outlet pressure sensor (12h), wherein the air outlet pressure sensor (12h) is configured to measure the air pressure of air drawn from the drum (111) and provide an outlet air pressure signal, wherein the control input signal comprises the outlet air pressure signal, - an air inlet pressure sensor (12h2), wherein the air inlet pressure sensor (12h2) is configured to measure the air pressure of the hot air fed into the drum (111) and to provide an inlet air pressure signal, wherein the control input signal comprises the inlet air pressure signal, - a crack detection sensor (12e), wherein the crack detection sensor (12e) is configured to detect the presence of first and / or second cracks in the coffee beans during roasting and to provide a crack detection signal, wherein the control input signal comprises the crack detection signal.

4. The coffee roaster (1) according to any of the preceding claims 1-2, wherein the rear wall (11111) is realized as a sandwich structure comprising an outer layer in thermal contact with the drum heater (116), an aluminum core layer and a food grade inner layer.

5. The coffee roaster (1) according to any one of the preceding claims 1-2, further comprising a drum inlet baffle (1114), wherein the drum inlet baffle (1114) is arranged to alternately open or close the drum inlet (11112), wherein the selected roasting profile comprises selected pre-roasting conditions, wherein the control unit (13) is configured to - generating a pre-bake control output signal as part of said control output signal, - Based on the control input signal, determining whether the selected pre-baking condition is met, and controlling the drum inlet damper (1114) to open the drum inlet (11112) when the selected pre-baking condition is met.

6. The coffee roaster (1) according to any one of the preceding claims 1-2, further comprising a drum outlet baffle (1115), wherein the drum outlet baffle (1115) is arranged to alternately open or close the drum outlet (11113); The control unit (13) is configured to control the drum outlet baffle (1115) to open the drum outlet (11113) when the baking end condition is met.

7. The coffee roaster (1) according to claim 6, further comprising a cooling unit (14), wherein the cooling unit (14) comprises a) a cooling container (141) having a cooling container inlet (1411), wherein the cooling container inlet (1411) is coupled to the drum outlet (11113) via the drum outlet baffle (1115), b) a cooling medium supply device, wherein the cooling medium supply device comprises - a cooling air supply device (144), wherein the cooling air supply device (144) is fluidly coupled to the inner cooling container space to feed cooling air into the cooling container (141), and / or - a cooling water supply (145), wherein the cooling water supply comprises a nozzle arrangement, wherein the nozzle arrangement is configured for spraying cooling water onto the coffee beans inside the cooling container (141).

8. The coffee roaster (1) according to claim 7, wherein the cooling vessel (141) is fluidly coupled to the inner drum space of the drum (111), thereby enabling cooling air to be transferred from the cooling vessel (141) into the drum (111) and to be extracted from the drum by an exhaust air extractor (115).

9. The coffee roaster (1) according to any one of the preceding claims 1 to 2, wherein: The coffee roaster (1) further comprises an exhaust gas treatment unit (15, 15'), wherein the exhaust gas treatment unit (15, 15') comprises a catalyst (157b'), the catalyst (157b') being configured to catalyze one or more components of the exhaust gas extracted from the drum.

10. The coffee roaster (1) according to claim 9, wherein the exhaust gas treatment unit (15, 15') comprises an exhaust gas heater (157a') and an exhaust gas cooler (157c'), wherein the exhaust gas heater (157a') is fluidly arranged upstream relative to the catalyst (157b'), and the exhaust gas cooler (157c') is fluidly arranged downstream relative to the catalyst (157b').

11. The coffee roaster (1) according to any of the preceding claims 1-2, further comprising a grounds separator (156, 19).

12. The coffee roaster (1) of claim 11, further comprising a fire extinguisher (194') configured to extinguish a fire in the grounds separator (156, 19).

13. The coffee roaster (1) according to any of the preceding claims 1-2, wherein the control unit (13) is configured to control the positive pressure device (1142) to change the air flow of the hot air depending on the progress of the roasting process.

14. The coffee roaster (1) according to any one of the preceding claims 1-2, wherein: The control unit (13) is configured to be operatively coupled to a remote computer system (2) and to receive a selected roasting profile from the remote computer system (2).

15. The coffee roaster (1) according to claim 14, wherein the control unit (13) is configured to acquire sensor data during the coffee bean roasting process to transmit the acquired sensor data and / or data derived from the acquired sensor data to the remote computer system (2).

16. The coffee roaster (1) of claim 1, wherein the positive pressure device comprises an intake fan.

17. The coffee roaster (1) according to claim 7, wherein the cooling air supply device (144) is a cooling fan.

18. The coffee roaster (1) according to claim 8, wherein the cooling container (141) is fluidly coupled to the inner drum space of the drum (111) in a fluid-tight manner.

19. The coffee roaster (1) of claim 11, wherein the grounds separator (156, 19) comprises a cyclone separator.

20. The coffee roaster (1) according to claim 13, wherein controlling the positive pressure device (1142) is controlling the rotation speed of an intake fan.

21. A coffee roasting system, wherein the coffee roasting system comprises: a) A coffee roaster (1) according to any one of claims 14 or 15, b) a remote computer system (2), wherein the remote computer system (2) is configured to store a plurality of available roasting curves, and to receive a user input for selecting a selected roasting curve from the plurality of available roasting curves, and to transmit the selected roasting curve to the control unit (13).

22. A method of roasting coffee beans, wherein the method comprises using a coffee roaster (1) according to any one of claims 1 to 20 and / or a coffee roasting system according to claim 21.

23. A method of brewing coffee, wherein the method comprises using a coffee roaster (1) according to any one of claims 1 to 20 and / or a coffee roasting system according to claim 21.

Images