Espresso machine with cold BREW mode

Abstract

An espresso machine for producing an espresso coffee beverage from coffee grounds held by a portafilter, the espresso machine including a water tank, a group head for receiving the portafilter, a pump between the water tank and the group head for pumping water from the water tank toward the group head, a heater between the pump and the group head, the heater being selectively operable such that either heated or non-heated water is provided to the group head.

Description

ESPRESSO MACHINE WITH COLD BREW MODEFIELD

[0001] This invention relates to an espresso machine for producing a coffee beverage.BACKGROUND

[0002] Existing espresso machines provide a versatile device for producing milk and non-milk inclusive coffee beverages, using a small quantity of concentrated coffee beverage, typically called an espresso shot. The extraction of an espresso shot typically occurs at high temperature (often between 90 °C- 100 °C) and high pressures (typically at about 9 bar). These extractions parameters create a profile of coffee flavour that is quite variable and sensitive to the precise extraction parameters, including extraction time.

[0003] Cold brew is a technique of extracting a coffee beverage from coffee grounds at comparatively low temperatures. Both room temperature water and iced water, close to 0 °C, may be used to extract cold brew. Cold brew is typically produced at ambient pressure, such as by slow- drip extraction or pour-over extraction. Cold brew extraction tends to create a different profile of coffee flavour compared to espresso extraction, due to the different temperatures and pressures employed.

[0004] It would be desirable to provide the option in an espresso machine of providing a beverage with a flavour profile similar to cold brew extraction.SUMMARY

[0005] It is an object of the present invention to at least substantially address one or more of the above desires, or at least provide a useful alternative to the above-mentioned espresso machines.

[0006] In a first aspect there is disclosed an espresso machine for producing an espresso coffee beverage from coffee grounds held by a portafilter, the espresso machine including: a water tank; a group head for receiving the portafilter; a pump between the water tank and the group head for pumping water from the water tanktoward the group head; a heater between the pump and the group head, the heater being selectively operable such that either heated or non-heated water is provided to the group head.

[0007] Preferably, the espresso machine further includes a steam wand having a nozzle for providing a steam jet suitable for frothing milk; and a wand valve between the heater and the steam wand, wherein the wand valve is operable to provide fluid communication between the heater and the steam wand, wherein the heater is further selectively operable to provide steam to the steam wand.

[0008] Preferably, the espresso machine further includes: a venturi nozzle located between the steam wand and the wand valve; and an air pump connected to the venturi nozzle such that the air pump is selectively operable to provide an air flow for mixing with the steam being provided to the steam wand.

[0009] Preferably, the espresso machine further includes: a hot water outlet for providing a flow of heated water from a location other than the group head. an outlet valve between the heater and the hot water outlet, wherein the outlet valve is operable to provide fluid communication between the heater and the hot water outlet.

[0010] Preferably, the espresso machine further includes a group head valve, and the group head valve is operable to provide fluid communication between the heater and the group head.

[0011] Preferably, the espresso machine further includes a drip tray, and wherein: when the group head valve is operated to block fluid communication between the heater and the group head, fluid communication between the heater and the steam wand valve is provided, when the steam wand valve is operated to block fluid communication between the heater and the steam wand, fluid communication between the heater and the outlet valve is provided, and when the outlet valve is operated to block fluid communication between the heater and the hot water outlet, fluid communication between the heater and the drip tray is provided.

[0012] Preferably, the espresso machine further includes a second group head valve, and the second group head valve is operable to provide fluid communication between the group head and the driptray, such that the water provided by the heater to the group head flows to the drip tray instead of through the portafilter held by the group head.

[0013] Preferably, the espresso machine further includes a group head heater located adjacent the group head and / or between the group head and the heater, the group head heater being selectively operable to heat the group head and / or the water immediately prior to entering the group head.

[0014] In a second aspect, there is disclosed a method of using the espresso machine of the first aspect for preparing an espresso coffee beverage, the espresso machine further including a controller for controlling operation of the pump and the heater, the method including the steps of: inserting a portafilter holding coffee grounds into the group head; the controller, using the pump, delivering a pre-infusion dose of water from the water tank to the group head; the controller, using the pump, delivering an extraction dose of water from the water tank to the group head.

[0015] Preferably, the pre-infusion dose of water and / or the extraction dose of water are delivered as non-heated water, without operation of the heater.

[0016] Preferably, the pre-infusion dose is delivered as heated water, and the extraction dose is delivered as non-heated water.

[0017] Preferably, during delivery of the pre-infusion dose the controller operates the group head heater to heat water, and does not operate the heater.

[0018] Preferably, when the non-heated water flows through the heater prior to being delivered to the group head.

[0019] Preferably, the method further includes the step of: the controller, using the pump, delivering a cooling dose of water from the water tank through the heater to absorb heat from the heater.

[0020] Preferably, the cooling dose is delivered to the drip tray.

[0021] Preferably, the cooling dose is delivered between the pre-infusion dose and the extraction dose.

[0022] Preferably, the espresso machine includes a user interface and a temperature sensor adapted to provide a temperature signal to the controller indicative of a temperature of the water provided to the group head, wherein the method further includes the steps of: the controller determining, based on the temperature signal, whether the temperature of the water is above a threshold temperature; and the controller causing the user interface to display a prompt to deliver the cooling dose.

[0023] Preferably, the espresso machine includes a user interface providing choice between a group of hot coffee beverages and a group of cold coffee beverages, wherein the method further includes the step of: when the controller determines that the group of cold coffee beverages is selected using the user interface, ceasing operation of the heater.

[0024] Preferably, the method further includes the step of: the controller ceasing operation of the pump between the pre-infusion dose and the extraction dose to provide a blooming period.

[0025] Preferably, the espresso machine includes a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head, and the controller determines a length of the blooming period using a blooming criterion, based on at least one of: a blooming time period; and the pressure signal.

[0026] Preferably, the espresso machine includes one or more of: a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head; a flow rate sensor to provide a flow rate signal based on a flow rate of the water provided to the group head; and a scale to provide a weight signal based on a weight of the espresso coffee beverage extracted, wherein the controller determines a length of pump operation for the pre-infusion dose using a preinfusion criterion, based on at least one of: a pre-infusion time period; the pressure signal;the flow rate signal; and the weight signal.

[0027] Preferably, the controller adjusts the pre-infusion criterion based on whether the heater is operated.

[0028] Preferably, the controller adjusts the pre-infusion criterion based on whether the group head heater is operated.

[0029] Preferably, the espresso machine includes one or more of: a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head; a flow rate sensor to provide a flow rate signal based on a flow rate of the water provided to the group head; and a scale to provide a weight signal based on a weight of the espresso coffee beverage extracted, wherein the controller determines a length of pump operation for the extraction dose using an extraction criterion, based on at least one of: an extraction time period; the pressure signal; the flow rate signal; and the weight signal.

[0030] Preferably, the controller adjusts the extraction criterion based on whether the heater is operated.

[0031] Preferably, the controller adjusts the extraction criterion based on whether the group head heater is operated.

[0032] Preferably, the espresso machine includes a grinder and a user interface providing choice between a group of hot coffee beverages and a group of cold coffee beverages and including a grind setting indicator, wherein the method further includes the step of: the controller determining whether a previous beverage extraction was selected from the group of cold coffee beverages or the group of hot coffee beverages with the grind setting indicatorcorrespondingly indicating a cold beverage grind setting or a hot beverage grind setting; and when the user interface receives a choice from the respective opposite group of hot coffee beverages or the group of cold coffee beverages, the controller causing the user interface to display a prompt to change the grind setting indicator to the corresponding hot or cold beverage grind setting.

[0033] Preferably, the controller stores the hot beverage grind setting and the cold beverage grind setting in memory, such that the hot and cold beverage grind settings are retrievable from memory by the controller.

[0034] Preferably, the controller determines the hot beverage grind setting by adding a predetermined grind setting interval to the cold beverage grind setting.BRIEF DESCRIPTION OF THE DRAWING

[0035] Preferred embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, wherein:

[0036] FIG. 1 shows an espresso machine according to a preferred embodiment of the invention.

[0037] FIG. 2 shows a hydraulic diagram of the espresso machine of FIG. 1.

[0038] FIG. 3 shows a system diagram of the espresso machine of FIG. 1.

[0039] FIG. 4 shows a flow chart of a beverage production method using the espresso machine of FIG. 1.

[0040] FIG. 5 shows a flow chart of a cold pre-infusion of the method of FIG. 4.

[0041] FIG. 6 shows a flow chart of a hot pre-infusion of the method of FIG. 4.

[0042] FIG. 7 shows a cold extraction of the method of FIG. 4.

[0043] FIG. 8 shows a cooling dose of the method of FIG. 4.

[0044] FIG. 9 shows a blooming method of the method of FIG. 4.

[0045] FIG. 10 shows user interface elements for actuating a grind cycle.

[0046] FIG. 11 shows user interface elements for actuating a beverage production cycle.

[0047] FIG. 12 shows user interface elements for actuating a milk frothing cycle.

[0048] FIG. 13 shows user interface elements for actuating a hot water delivery.

[0049] FIG. 14 shows a chart of a temperature signal from a temperature probe of the espresso machine of FIG. 1 having a thermoblock type heater during a beverage extraction and a subsequent cooling dose.

[0050] FIG. 15 is a detailed view of the cooling dose shown in FIG. 14.

[0051] FIG. 16 shows a chart of a temperature signal from a temperature probe of the espresso machine of FIG. 1 having a thin film type heater during a beverage extraction and a subsequent cooling dose.

[0052] FIG. 17 is a detailed view of the cooling dose shown in FIG. 16.

[0053] FIG. 18 shows user interface elements of the espresso machine of FIG. 1, prompting delivery of a cooling dose.

[0054] FIG. 19 shows a user interface flow chart for the espresso machine of FIG. 1 prompting change of a grind setting indicator due to selection from a group of cold coffee beverages.

[0055] FIG. 20 shows a user interface flow chart for the espresso machine of FIG. 1 prompting change of a grind setting indicator due to selection from a group of hot coffee beverages.DETAILED DESCRIPTION

[0056] An espresso machine 100 according to a preferred embodiment of the invention, as shown in FIG. 1, may be used to produce an espresso coffee beverage (not shown) from coffee grounds 12 held by a portafilter 10. The espresso machine 100 may include a grinder 220 for providing the coffee grounds 12. The espresso machine 100 is preferably controlled by a controller 102. The machine 100 may further include a user interface 230 to provide user input for the controller 102and / or for the controller 102 to provide information to the user. The espresso machine 100 includes a water tank 120 configured to hold a quantity of water 122. The machine 100 further includes a group head 130 for receiving the portafilter 10, for example by use of a bayonet fitting 131 in the group head 130 that is engaged by tabs 14 of the portafilter 10. As shown in FIG. 2, the machine 100 further includes a pump 140 between the water tank 120 and the group head 130, for pumping the water 122 from the water tank 120 toward the group head 130. The machine 100 further includes a heater 150 between the pump 140 and the group head 130. The heater 150 is preferably a low thermal mass heater, such as a thick film resistance heater. The heater 150 is selectively operable such that the water 122 provided to the group head 130 is either heated or non-heated. Preferably, the water 122 from the water tank 120 must pass through the heater 150 to reach the group head 130. The machine 100 may also include a drip tray 200 for capturing overflows from various locations in the machine 100, including from overflowing a receptacle into which the espresso coffee beverage is delivered. The group head 130 may include a group head valve 134, operable to selectively provide fluid communication between the heater 150 and the group head 130. The group head 130 may further include a second group head valve 136, operable to selectively provide fluid communication between the group head 130 and the drip tray 200. In this way, when the second group head valve 136 provides fluid communication between the group head 130 and the drip tray 200, water 122 provided by the heater 150 to the group head 130 flows to the drip tray 200 instead of through the portafilter 10 held by the group head 130. The group head 130 may further include a group head heater 138 located adjacent the group head 130 and / or between the group head 130 and the heater 150. The group head heater 138 is selectively operable to heat the group head 130 and / or the water 122 immediately prior to entering the group head 130. When extracting a standard espresso coffee beverage, the group head heater 138 allows better control of the temperature of the water 122 in the group head 130, due to less heat transfer from the heated water 122 to the group head 130.

[0057] As shown in FIG. 2, the espresso machine 100 may further include a steam wand 160 having a nozzle 162 for providing a steam jet suitable for frothing milk. A wand valve 164 may be positioned between the heater 150 and the steam wand 160, operable to selectively provide fluid communication between the heater 150 and the steam wand 160. Accordingly, the heater 150 and pump 140 may be operated to provide steam to the steam wand 160, for example by increasing the power applied to the heater 150 and / or decreasing the pump rate of the pump 140, such that the water flowing through the heater 150 is superheated to steam. Preferably, when the group head valve 134 is operated to block fluid communication between the heater 150 and the group head 130,fluid communication between the heater 150 and the wand valve 164 is provided instead, for example by use of a hydraulic 3 / 2 valve.

[0058] Remaining with FIG. 2, the espresso machine 100 may further include a venturi nozzle 170 located between the steam wand 160 and the wand valve 164. The machine 100 may also include an air pump 180 connected to the venturi nozzle 170 such that the air pump 180 is selectively operable to provide an air flow 182 for mixing with the steam in the venturi nozzle 170, such that a proportion of the flow through the nozzle 162 is the air flow 182.

[0059] The espresso machine 100 may further include a hot water outlet 180 for providing a flow of heated water from a location other than the group head 130. The machine 100 may also include an outlet valve 184 between the heater 150 and the hot water outlet 180, operable to selectively provide fluid communication between the heater 150 and the group head 130. Preferably, when the wand valve 164 is operated to block fluid communication between the heater 150 and the steam wand 160, fluid communication between the heater 150 and the outlet valve 184 is provided instead, for example by use of a hydraulic 3 / 2 valve. Further, when the outlet valve 184 is operated to block fluid communication between the heater 150 and the hot water outlet 180, fluid communication between the heater 150 and the drip tray 200 is provided.

[0060] As shown in FIG. 3, the machine 100 may further include a pressure sensor 210 and one or more temperature sensors 216, and / or as shown in FIG. 2, a flow rate sensor 212, and a scale 214. The controller 102 is preferably operably connected to the pump 140, the heater 150. Further, the pressure sensor 210 may be adapted to provide a pressure signal to the controller 102 indicative of a pressure of the water 122 provided to the group head 130. Similarly, the flow rate sensor 212 may be adapted to provide a flow rate signal to the controller 102 indicative of a flow rate of the water 122 provided to the group head 130. Similarly, the temperature sensor 216 may be adapted to provide a temperature signal to the controller 102 indicative of a temperature of the water 122 provided to the group head 130. Similarly, the scale 214 may be adapted to provide a weight signal to the controller 102 indicative of a weight of the extracted espresso coffee beverage.

[0061] Use of the machine 100 will now be discussed.

[0062] As shown in FIG. 4, use of the machine 100 for preparing an espresso coffee beverage might include, firstly, inserting the portafilter 10 holding the coffee grounds 12 into the group head 130. The, at step S 101 , the controller 102, using the pump 140, delivers a pre-infusion dose of water 122from the water tank 120 to the group head 130. Subsequently, at step S103, the controller 102, using the pump 140, delivers an extraction dose of water 122 from the water tank 120 to the group head 130. As noted in FIG. 4, the pre-infusion dose and / or the extraction dose may be delivered as non-heated water 122, without operation of the heater 150. For the avoidance of doubt, the extraction dose may also be delivered using heated water 122, with operation of the heater 150, for extraction of a standard espresso coffee beverage. In one embodiment, the pre-infusion dose may be delivered as heated water 122, and the extraction dose is delivered as non-heated water 122. Preferably, during delivery of the pre-infusion dose using heated water 122, the controller 102 operates the group head heater 138, but does not operate the heater 150. The group head heater 138 may have a lower power rating than the heater 150, and the volume of water 122 used for the preinfusion dose is typically small enough to not require use of the heater 150. Further, the water 122 of the pre-infusion dose is typically held within a cavity 16 defined by the portafilter 10 and the group head 130, allowing a longer contact time between the water 122 and the group head heater 138 compared to an extraction dose. However, as shown in the hydraulic diagrams of FIGS. 2 and 3, the non-heated water 122 flows through the heater 150 prior to being delivered to the group head 130.

[0063] Delivery of the pre-infusion dose at step S101 is shown in more detail in FIGS. 5 and 6. FIG. 5 shows the delivery of a pre-infusion dose of non-heated water, while FIG. 6 shows the delivery of a pre-infusion dose of heated water. Turning to FIG. 5, step S127, the controller 102 ceases operation of the heater 150 and the group head heater 138. At step S129 the controller 102 operates the pump 140 at a first power. At step S 131 , the controller 102 operates the group head valve 134 to provide fluid communication between the heater 150, and thus the pump 140, and the group head 130, allowing the pre-infusion dose to be delivered to the group head 130. At step S133 the controller determines a pre-infusion criterion based on at least one of a pre-infusion time period, the pressure signal, the flow rate signal, and the weight signal. If the pre-infusion criterion is met, the controller 102 proceeds with the next step of the beverage extraction process, being either providing a blooming period, or delivering the extraction dose.

[0064] The delivery of a pre-infusion dose using heated water 122 shown in FIG. 6 differs from the cold pre-infusion shown in FIG. 5 in that at step S127 the controller 102 may only disable one or none of the heater 150 and the group head heater 138. Further, the controller 102 may operate the heater 150 and / or the group head heater 138 at a target pre-infusion temperature. At step S129, the controller 102 may operate the pump 140 at a second power. At step S 133, the controllerdetermines the pre-infusion criterion similarly to FIG. 5, however the controller 102 adjusts the preinfusion criterion based on whether the heater 150 and / or the group head heater 138 is operated.

[0065] If the pre-infusion dose and / or the extraction dose are to be delivered using non-heated water 122, and the heater 150 was previously used for another beverage extraction process, or is otherwise at above room temperature, the controller 102 may as shown in FIG. 4 at step S105, using the pump 140, deliver a cooling dose of water 122 from the water tank 120 through the heater 150 to absorb heat from the heater 150. Step S105 is shown in more detail in FIG. 8. The cooling dose may be delivered to the group head 130, by operating the group head valve 134, provided that the portafilter 10 is not yet engaged with the group head 130. In preferred embodiments, the cooling dose is delivered to the drip tray 200, by operation of the group head valve 134, the wand valve 164, and the outlet valve 194, to block fluid communication between the heater 150 and the group head 130, the steam wand 160, and the fluid outlet 190, respectively. The cooling dose may also be delivered to the hot water outlet 190, by similar operation, except for operation of the outlet valve 194 to provide fluid communication between the heater 150 and the fluid outlet 190. As shown in FIG. 8, step S105 may include step S107 of turning off the heater 150 and the group head heater 138, step S109 of operating the pump 140, and step Si l l of operating the group head valve 130 and the wand valve 164. Operation of the outlet valve 184 depends on whether the cooling dose is to be delivered to the drip tray 200 or the fluid outlet 180. At step SI 12, the controller 102 determines a cooling criterion based on one or more of the temperature signal and a cooling time period. When the controller 102 has determined that the cooling criterion has been met, the controller 102 has finished step S105 and ceases operating the pump 140. As shown in FIGS. 14 to 17, the cooling dose 103 may be provided using different amounts of water over different periods of time, depending on the structural elements of the espresso machine 100. In one embodiment, where the heater 150 includes a thermoblock type heater, as shown in FIGS. 14 and 15, the cooling dose may include delivery of about 600 ml of water of an 8 min period. In another embodiment, where the heater 150 includes a thin film type heater, as shown in FIGS. 16 and 17, the cooling dose may include delivery of about 150 ml of water over a 40 s period. A preferred cooling criterion is for the temperature sensor 216 to indicate a temperature of under 35 °C in the region of the group head 130.

[0066] In an embodiment where the pre-infusion dose is delivered using heated water 122, the cooling dose may be delivered between the pre-infusion dose and the extraction dose.

[0067] Reverting to FIG. 4, following step S103 of delivering the pre -infusion dose, the controller 102 may execute step SI 13 of ceasing operation of the pump 140 before delivering the extractiondose to provide a blooming period. Step S 113 is described in more detail in FIG. 9. At step S 115 the controller 102 may provide a notification using the user interface 230 that the pump 140 may cease operating for a period of time to provide a blooming period. At step S 117 the controller 102 may cease operation of the heater 150. At step SI 19 the controller 102 may cease operation of the pump 140. At step S121 the controller 102 may operate the group head valve 134 to prevent backflow of water 122 from the group head 130 toward the heater 150. At step S123 the controller 102 may operate the wand valve 164 and optionally the outlet valve 184 to evacuate any excess water between the pump 140 and the group head valve 134 via the drip tray 200 or the fluid outlet 180. At step S125 the controller 102 determines a blooming criterion based on at least one of a blooming time period and the pressure signal from the pressure sensor 210. If the blooming criterion is satisfied, the controller 102, at step S103 delivers the extraction dose.

[0068] The delivery of the extraction dose at step S103 is shown in more detail at FIG. 7. At step S 135, the controller 102 may cease operation of the heater 150 and the group head heater 138. At step S137, the controller 102 may operate the group head valve 134 to provide fluid communication between the pump 140 and the group head 130 through the heater 150. At step S139, the controller 102 may act on user input received via the user interface 230 to determine whether a short coffee beverage is requested, or a long coffee beverage is requested. If a short coffee beverage is requested, at step S 141, the controller 102 may operate the pump 140 at a third power to deliver the extraction dose to the group head 130. At step S143, the controller 102 may determine an extraction criterion based on at least one of an extraction time period, the pressure signal, the flow rate signal, and the weight signal. If the controller 102 determines that the extraction criterion is met, at step S145, the controller 102 may end the beverage extraction process. If, alternatively, a long coffee beverage is requested, at step S147, the controller 102 may operate the pump 140 at a fourth power to deliver the extraction dose to the group head 130. The fourth power is lower than the third power, such that when the extraction dose is delivered there is a lower amount of cavitation occurring in the coffee grounds 12 during the extraction process, leading to a lower amount of crema in the extracted coffee beverage. At step S149, the controller 102 may determine an extraction criterion based on at least one of an extraction time period, the pressure signal, the flow rate signal, and the weight signal. If the controller 102 determines that the extraction criterion is met, at step S145, the controller 102 may end the beverage extraction process.

[0069] The controller 102 may, at steps S143, S149, adjust the extraction criterion based whether the heater 150 and / or the group head heater 138 is operated.

[0070] FIGS. 10 to 13 show the user interface 230 at various positions through the method shown in FIGS. 4 to 9.

[0071] As shown in FIG. 10, the controller 102 may display, when preparing a milk-based coffee beverage, using the user interface 220, a grind icon 232, an extract icon 234, and a froth icon 236. The grind icon 232 may show an image of the portafilter 10, the extract icon 234 may show a container for receiving the extracted coffee beverage, the froth icon 236 may show a container for frothing milk. The grind icon 232 may include a grind setting indicator 238 showing a number indicative of a grind size setting. On selection of the grind icon 232, the controller 102 may operate the grinder 220 for producing the coffee grounds 12. While the grinder 220 is operated, the grind setting indicator 238 may show a progress bar, or a working indicator, such as the rotating arrows shown in FIG. 10. When the operation has completed, the grind setting indicator 238 may show a finish indicator, such as the green circle shown in FIG. 10.

[0072] Turning to FIG. 11, on selection of the extract icon 234, the extract icon 234 may show an empty container and a progress bar or icon. While the controller 102 operates the heater 150 to prepare the pre-infusion dose, the container remains empty and may pulse between different opacity levels less than 100%, and the progress bar does not progress. When the controller 102 operates the pump 140 and / or heater 150 to deliver the pre-infusion dose, the progress bar begins to increment, and may show an indication of time elapsed since commencement of the pre-infusion dose. The container is still shown as empty. When the controller 102 operates the pump 140 and / or heater 150 to deliver the extraction dose, the extract icon 234 may show a small amount of beverage in the container with streams of beverage pouring into the container. At a time less than a projected extraction time period, the extract icon 234 may show a medium amount of beverage in the container with streams of beverage pouring into the container. When the extraction criterion has been met, and the controller 102 ceases delivering the extraction dose, the extract icon 234 may show a full amount of beverage in the container without streams of beverage pouring into the container. The extract icon 234 may be used to alter the extraction criterion by adjusting the extraction time period and / or adjusting a target extraction volume.

[0073] Turning to FIG. 12, on selection of the froth icon 236, the froth icon 236 may be shown at partial opacity and pulse between different opacity levels less than 100% while the controller 102 operates the heater 150 to prepare for delivering the steam flow to the steam wand 160. When the controller 102 has operated the group head valve 134 and the wand valve 164 to provide the steam flow to the steam wand 160, the froth icon 236 may show a cut-away container for frothing milkwith a small volume of milk in the container. The froth icon 236 may provide an indication of a temperature of the milk being frothed by the steam wand 160. For example by providing a read-out of the milk temperature and / or a progress bar of the temperature of the milk relative to a target temperature of the milk. At a point between commencement of the frothing action and reaching of the target temperature of the milk, the froth icon 236 may show the cut-away container with a medium volume of milk in the container. When the controller 102 operates one or more of the pump 140, heater 150, group head valve 134, and the wand valve 164 to cease the frothing operation, the froth icon 236 may show the cut-away container with a large volume of milk in the container. The progress bar may show a green circle.

[0074] Turning to FIG. 13, when a selection has been received by the user interface 230 to prepare a non-milk-based coffee beverage, the froth icon 236 may be replaced by a water icon 240. On selection of the water icon 240, the water icon 240 may be shown at partial opacity and pulse between different opacity levels less than 100% while the controller 102 operates the heater 150 to prepare for delivering delivery of water 122 to the fluid outlet 180. When the controller 102 has operated the group head valve 134, the wand valve 164, and the outlet valve 184 to deliver water 122 to the fluid outlet 180, the water icon 240 may show the container for receiving the coffee beverage with a small amount of water and a stream of water flowing into the container. The water icon 240 may show a progress bar based on the amount of water 122 the controller 102 expects to deliver to the fluid outlet 180. The water icon 240 may also show an indication of time passed since the controller 102 started delivering water 122 to the fluid outlet 180. At a time between the controller 102 starting deliver of water 122 to the fluid outlet 180 and an expected completion of the delivery, the water icon 240 may show the container with a medium amount of water and a stream of water flowing into the container. When the container 102 stops delivering water 122 to the fluid outlet 180, the water icon 240 may show the container with a large volume of water and without a stream of water flowing into the container. The progress bar may be a green circle.

[0075] The espresso machine 100 may have a top-level user interface 230 showing different possible beverages to extract using the machine 100. The possible beverages may be considered as two groups, a group of hot coffee beverages and a group of cold coffee beverages. The beverages need not be shown in any grouping in the user interface 230. When selecting a beverage, the user interface 230 may then change to a beverage level, shown in FIGS. 18 to 20, where various parameters of the beverage may be selected before commencing the extraction. The beverage level may include the grind icon 232, the extract icon 234 and the froth icon 236.

[0076] The controller 102 may be configured to determine whether a previous beverage extraction was selected from the group of hot coffee beverages or the group of cold coffee beverages. When the controller 102 determines that the previous extraction was from the group of hot coffee beverages, and the user selects to enter the beverage level of a cold coffee beverage, the controller 102 is adapted to cause the user interface 230 to display a prompt to 242 deliver the cooling dose. In another embodiment, the controller 102 may be adapted to determine, based on the temperature signal, whether the temperature of the water is above a threshold temperature, and subsequently cause the user interface to display the prompt to deliver the cooling dose.

[0077] It is preferred that the controller 102 is adapted to, when the user interface 230 is controlled to enter the beverage level of a cold coffee beverage, cease operation of the heater 150, to commence conductive cooling of the heater 150 and associated hydraulics, potentially avoiding the need for a cooling dose, or at least reducing the amount of water required to dissipate the heat from the heater 150.

[0078] As shown in FIGS. 19 and 20, the controller 102 may determine whether the previous beverage extraction was selected from the group of cold coffee beverages or the group of hot coffee beverages with the grind setting indicator 238 correspondingly indicating a cold beverage grind setting or a hot beverage grind setting. The cold and hot beverage grind settings are terms applied to the grind setting used to extract, correspondingly, the cold or the hot coffee beverage. When the user interface 230 receives a choice from the respective opposite group of hot coffee beverages or the group of cold coffee beverages, the controller 102 may cause the user interface 230 to display a prompt 244 to change the grind setting indicator 238 to the corresponding hot or cold beverage grind setting. The controller 102 may store the hot beverage grind setting and the cold beverage grind setting in memory, such that the hot and cold beverage grind settings are retrievable from memory by the controller 102. The controller 102 may update the respective hot or cold beverage grind settings in memory following successful a beverage extraction. The controller 102 may determine the hot beverage grind setting by adding a predetermined grind setting interval, shown as “Y” in FIG. 20, to the cold beverage grind setting.

[0079] Advantages of the espresso machine 100 will now be discussed.

[0080] Because the heater 150 is selectively operable, it is possible to provide non-heated water 122 to the group head 130 for performing a cold brew extraction using the espresso machine 100. The provision of the steam wand 160, hot water outlet 180 and the valves 134, 164, 184 allow foroperation of the espresso machine to provide classic espresso beverages, whether extracted using heated water, or non-heated water. The arrangement of the valves 134, 136, 164, 184 allows for provision of water 122 from a single pump 140 and heater 150 to a variety of end-points.Specifically, it allows the delivery of a cooling dose through the heater 150 to be delivered directly to the drip tray 200 to purge heat from the heater 150 and the hydraulic system to allow delivery of a non-heated pre-infusion or extraction dose. The use of the group head heater 138 allows the relatively fine-grained control of the temperature of the water 122 during the pre-infusion dose, when the water 122 is confined in the cavity 16. The use of the blooming period allows for an expulsion of carbon dioxide from the coffee grounds 12 and an absorption of water by the coffee grounds 12, resulting in a more predictable and complete extraction of the coffee beverage by the subsequent extraction dose.

[0081] Integers:10 portafilter 180 air pump12 coffee grounds 182 air flow14 tabs 190 hot water outlet16 cavity 192 flow of heated water100 espresso machine 194 outlet valve102 controller 200 drip tray120 water tank 210 pressure sensor122 water 212 flow rate sensor130 group head 214 scale134 group head valve 216 temperature sensor136 second group head valve 220 grinder138 group head heater 230 user interface140 pump 232 grind icon150 heater 234 extract icon160 steam wand 236 froth icon162 nozzle 238 grind setting indicator164 wand valve 240 water icon170 venturi nozzle

Claims

CLAIMS:

1. An espresso machine for producing an espresso coffee beverage from coffee grounds held by a portafilter, the espresso machine including: a water tank; a group head for receiving the portafilter; a pump between the water tank and the group head for pumping water from the water tank toward the group head; a heater between the pump and the group head, the heater being selectively operable such that either heated or non-heated water is provided to the group head.

2. The espresso machine of claim 1, wherein the espresso machine further includes a steam wand having a nozzle for providing a steam jet suitable for frothing milk; and a wand valve between the heater and the steam wand, wherein the wand valve is operable to provide fluid communication between the heater and the steam wand, wherein the heater is further selectively operable to provide steam to the steam wand.

3. The espresso machine of claim 1, wherein the espresso machine further includes: a venturi nozzle located between the steam wand and the wand valve; and an air pump connected to the venturi nozzle such that the air pump is selectively operable to provide an air flow for mixing with the steam being provided to the steam wand.

4. The espresso machine of claim 1, wherein the espresso machine further includes: a hot water outlet for providing a flow of heated water from a location other than the group head. an outlet valve between the heater and the hot water outlet, wherein the outlet valve is operable to provide fluid communication between the heater and the hot water outlet.

5. The espresso machine of claim 1, wherein the espresso machine further includes a group head valve, and the group head valve is operable to provide fluid communication between the heater and the group head.

6. The espresso machine of claim 5, when dependent from claims 2 and 1, wherein the espresso machine further includes a drip tray, and wherein:when the group head valve is operated to block fluid communication between the heater and the group head, fluid communication between the heater and the steam wand valve is provided, when the steam wand valve is operated to block fluid communication between the heater and the steam wand, fluid communication between the heater and the outlet valve is provided, and when the outlet valve is operated to block fluid communication between the heater and the hot water outlet, fluid communication between the heater and the drip tray is provided.

7. The espresso machine of claim 5, wherein the espresso machine further includes a second group head valve, and the second group head valve is operable to provide fluid communication between the group head and the drip tray, such that the water provided by the heater to the group head flows to the drip tray instead of through the portafilter held by the group head.

8. The espresso machine of claim 1, wherein the espresso machine further includes a group head heater located adjacent the group head and / or between the group head and the heater, the group head heater being selectively operable to heat the group head and / or the water immediately prior to entering the group head.

9. Method of using the espresso machine of claim 1 for preparing an espresso coffee beverage, the espresso machine further including a controller for controlling operation of the pump and the heater, the method including the steps of: inserting a portafilter holding coffee grounds into the group head; the controller, using the pump, delivering a pre-infusion dose of water from the water tank to the group head; the controller, using the pump, delivering an extraction dose of water from the water tank to the group head.

10. The method of claim 9, wherein the pre-infusion dose of water and / or the extraction dose of water are delivered as non-heated water, without operation of the heater.

11. The method of claim 10, wherein the pre-infusion dose is delivered as heated water, and the extraction dose is delivered as non-heated water.

12. The method of claim 10, when dependent from claim 8, wherein during delivery of the pre-infusion dose the controller operates the group head heater to heat water, and does not operate the heater.

13. The method of claim 10, wherein when the non-heated water flows through the heater prior to being delivered to the group head.

14. The method of claim 10, further including the step of: the controller, using the pump, delivering a cooling dose of water from the water tank through the heater to absorb heat from the heater.

15. The method of claim 14, when dependent from claim 6, wherein the cooling dose is delivered to the drip tray.

16. The method of claim 14, wherein the cooling dose is delivered between the preinfusion dose and the extraction dose.

17. The method of claim 14, wherein the espresso machine includes a user interface and a temperature sensor adapted to provide a temperature signal to the controller indicative of a temperature of the water provided to the group head, wherein the method further includes the steps of: the controller determining, based on the temperature signal, whether the temperature of the water is above a threshold temperature; and the controller causing the user interface to display a prompt to deliver the cooling dose.

18. The method of claim 10, wherein the espresso machine includes a user interface providing choice between a group of hot coffee beverages and a group of cold coffee beverages, wherein the method further includes the step of:when the controller determines that the group of cold coffee beverages is selected using the user interface, ceasing operation of the heater.

19. The method of claim 9, further including the step of: the controller ceasing operation of the pump between the pre-infusion dose and the extraction dose to provide a blooming period.

20. The method of claim 17, wherein the espresso machine includes a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head, and the controller determines a length of the blooming period using a blooming criterion, based on at least one of: a blooming time period; and the pressure signal.

21. The method of claim 9, wherein the espresso machine includes one or more of: a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head; a flow rate sensor to provide a flow rate signal based on a flow rate of the water provided to the group head; and a scale to provide a weight signal based on a weight of the espresso coffee beverage extracted, wherein the controller determines a length of pump operation for the pre-infusion dose using a pre-infusion criterion, based on at least one of: a pre-infusion time period; the pressure signal; the flow rate signal; and the weight signal.

22. The method of claim 19, wherein the controller adjusts the pre-infusion criterion based on whether the heater is operated.

23. The method of claim 20, when dependent from claim 8, wherein the controller adjusts the pre-infusion criterion based on whether the group head heater is operated.

24. The method of claim 9, wherein the espresso machine includes one or more of: a pressure sensor to provide a pressure signal based on a water pressure of the water provided to the group head; a flow rate sensor to provide a flow rate signal based on a flow rate of the water provided to the group head; and a scale to provide a weight signal based on a weight of the espresso coffee beverage extracted, wherein the controller determines a length of pump operation for the extraction dose using an extraction criterion, based on at least one of: an extraction time period; the pressure signal; the flow rate signal; and the weight signal.

25. The method of claim 22, wherein the controller adjusts the extraction criterion based on whether the heater is operated.

26. The method of claim 23, when dependent from claim 8, wherein the controller adjusts the extraction criterion based on whether the group head heater is operated.

27. The method of claim 10, wherein the espresso machine includes a grinder and a user interface providing choice between a group of hot coffee beverages and a group of cold coffee beverages and including a grind setting indicator, wherein the method further includes the step of: the controller determining whether a previous beverage extraction was selected from the group of cold coffee beverages or the group of hot coffee beverages with the grind setting indicator correspondingly indicating a cold beverage grind setting or a hot beverage grind setting; and when the user interface receives a choice from the respective opposite group of hot coffee beverages or the group of cold coffee beverages, the controller causing the user interface to display a prompt to change the grind setting indicator to the corresponding hot or cold beverage grind setting.

28. The method of claim 27, wherein the controller stores the hot beverage grind setting and the cold beverage grind setting in memory, such that the hot and cold beverage grind settings are retrievable from memory by the controller.

29. The method of claim 27, wherein the controller determines the hot beverage grind setting by adding a predetermined grind setting interval to the cold beverage grind setting.

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