Method and system for manufacturing coffee tablets

Abstract

A method for manufacturing coffee tablets comprises: i) providing a uniform wet weight of roasted coffee beans having a moisture content between 3 and 11% by weight; ii) feeding said wet weight to a dosing device; iii) placing a dose of wet coffee within a cavity of a forming tool, said cavity having a bottom surface (35a), a head surface (32a), and a peripheral surface, at least a portion (22a) of said bottom surface (35a), said head surface (32a), and the peripheral surface being configured to define a compression space (CS) for the wet coffee dose; iv) compressing the dose of wet coffee (DGC) within said cavity (22) to form a coffee tablet (1); v) removing the coffee tablet (1) from said cavity (22). Step iv) comprises compressing the dose of wet coffee (DGC) while said portion of the peripheral surface (22a) is heated at a different temperature, preferably a temperature lower than the temperature at which at least one of said bottom surface (35a) and said head surface (32a) is heated.

Description

Technical Field

[0001] The present invention relates to the coffee industry and has been developed with particular reference to the manufacture of tablets or similar dosage units without a functional casing, starting from roasted coffee bean powder for use in beverage preparation devices. The tablets obtained by the method and system according to the present invention are designed for preferred use on automatic and semi-automatic preparation machines, but their tendency for use on other preparation devices such as "moka" or "Neapolitan" type coffee makers, or coffee press type coffee makers, or percolator devices is not excluded.

Background Art

[0002] The preparation of liquid foods on a preparation machine or device starting from pre-divided doses of precursors is widely used, especially for the preparation of warm beverages such as espresso.

[0003] In some known solutions, the dose of the beverage precursor has a functional outer casing, i.e., it is packaged in a more or less tight capsule, and the corresponding preparation machine is designed such that the preparation liquid (typically water) passes through this capsule and distributes the beverage outwards. In the case of other preparation devices, the dose of the precursor is housed in a functional casing that is flexible and water-permeable, typically a paper casing commonly called a "pod". In some cases, the pods are intended for use on automatic or semi-automatic preparation machines, while in other cases they are intended for use on coffee makers or percolators. Even with these solutions, in any case, a flexible and permeable functional envelope is created to allow the flow of the preparation liquid to pass through.

[0004] The packaging of a single dose of precursor in its functional casing suggests various drawbacks, which are linked to a higher cost of the product, a greater complexity of the manufacturing process, the need for correct environmentally friendly disposal of used capsules or pods, and the environmental impact resulting from the associated gas emissions.

[0005] These problems have been addressed in the past by proposing the production of precursor dosing units having a self - standing structure that does not necessarily require a functional outer casing, especially in the form of tablets or pills. These tablets or pills can be collectively packaged in the same container, for example, a bag made of a material having good oxygen barrier properties, in order to avoid rapid deterioration of the product (typically due to oxidative degradation). Thus, these tablets are designed to be inserted directly into the associated preparation machine, i.e., without a beverage preparation process that assumes the use of a functional casing.

[0006] EP0229920A1 discloses a method for the preparation of coffee tablets involving the compression of a mass of roasted coffee bean particles having a moisture content of at least 3 wt% and an average coffee particle size of 0.4 mm to 2.0 mm at a compression force in the range of 20.7 MPa to 48.3 MPa. Preferably, the moisture content of the roasted coffee bean particles is 3 wt% to 6 wt%, their average size is 0.6 mm to 1.2 mm, and the compression force is 27.6 MPa to 41.4 MPa. The pressure used is such that the volume of the mass of roasted coffee bean particles is reduced to a value between 55% and 30% of the original volume of the wet weight. The final density of the tablets is between 0.60 and 0.95 g / cm 3 ³. The compression operation is carried out by placing a dose of coffee particles between opposing elements and pushing the elements towards each other. These opposing elements include a shaped mold defining a tubular pocket of a desired shape open at one end and a punch that slides and is received within the pocket.

[0007] In the first practical example of the aforementioned document, a single tablet is obtained from 60 grams of wet coffee powder, the tablet having a diameter of 100 mm and a thickness of about 9.2 mm and having flat end walls. Such a tablet can be used to prepare about 8 to 10 cups of coffee. In different comparative examples, five different portions of 4% wet coffee powder having an average coffee particle size of 1 mm were subjected to different compression forces starting from a thickness of 23.5 mm. The results are as follows. [Table 1]

Table 1

[0008] WO2019 / 106413A1 discloses another method for the preparation of coffee tablets, which includes grinding coffee beans to obtain the corresponding powder, subsequent humidification of the coffee powder in a cloud of cold steam, and the formation of a dose of wet coffee powder by insertion into a molding mold. The dose is then heated and pressed to form a tablet having the desired shape by compression that does not cause deformation of the individual coffee particles. The humidification of the coffee powder is carried out while filling the molding mold, the powder being heated in both the filling phase and the compression phase, and the temperature of the mold part being raised to a predetermined value between 60 and 86 °C to determine the sintering of the particles of the coffee powder, whereby a tablet having a compact and stable form is obtained. The size of the coffee particles is between 200 and 1000 microns depending on the extraction method of the beverage intended for the tablet, and the PSD (particle size distribution) is 65 - 90% within 200 microns. The dose of coffee powder is 6 - 12 grams. The cold steam is obtained from an aqueous solution of 2 - 10% sodium chloride and 2 - 10% sucrose. The supply of cold steam is carried out by pulses, and the supply time does not exceed 2 seconds.

[0009] The examples in the literature provide two possible methods where the starting materials are roasted coffee with a moisture content between 3 - 6% and green coffee with a moisture content between 9 - 12%. In both cases, the weight of the starting dose is 7 and 12 g. By compressing the dose at a pressure between 40 - 160 MPa, tablets were obtained having a mass of 7.2 and 11.8 g, a density between 0.95 - and 1.29 g / cm 3 and a residual moisture of 3 - 4.5%.

[0010] WO2021 / 033011A1 discloses a further process for manufacturing coffee tablets, where a dose of coffee powder is wetted, fed into a forming mold, and then heated and subjected to compression. The starting dose comprises at least a first fraction of powder having a particle size between 500 - 900 microns each and a second fraction of powder having a particle size of less than 200 microns to form tablets with a weight between 6 - 12 grams, where the first fraction is 70 - 90 wt% and the second fraction is 10 - 30 wt%. The humidification is carried out by first spraying a solution onto the inner surface of the forming mold and then successively continuously feeding 50 - 70% of the second fraction, then 100% of the first fraction, and finally the remaining 50 - 30% of the second fraction, followed by compression by a punch while heating simultaneously.

[0011] The surface layer of the tablet is heated by electrical heating of the mold and punch up to 55 - 85 °C or alternatively by microwaves. The effect of the shown method is that the first fraction of larger particles is present inside the tablet and the outside is surrounded by a dense layer of the finest particles.

[0012] The known methodologies shown have several drawbacks, which are related to the inability to achieve the exact sensory acceptance profile in the final beverage and problems with the integrity of the tablets, which are caused, for example, by dust, breakage, and especially the formation of transverse cracks in the tablets. SUMMARY OF THE INVENTION

[0013] In its general sense, the present invention aims to solve the above-mentioned disadvantages by an improved method for the manufacture of coffee powder tablets. A secondary object of the present invention is to show one such method that can be implemented in a simple manner.

[0014] According to the present invention, at least one of the aforementioned objects is achieved by a method, a system, and a tablet having the characteristics shown in the appended claims. The claims form an indispensable part of the technical teaching provided herein in connection with the present invention.

Brief Description of the Drawings

[0015] Further objects, characteristics, and advantages of the present invention are provided by the following description with reference to the accompanying drawings, which are provided purely by way of non-limiting example.

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DETAILED DESCRIPTION OF THE INVENTION

[0016] References in this specification to an embodiment indicate that the particular configurations, structures, or characteristics described in connection with the embodiment are included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment," "in various embodiments," etc., which may appear in different places in this specification, are not necessarily all referring to the same embodiment. Additionally, the particular forms, structures, or characteristics defined in this specification may be combined in any suitable manner, or even in a manner different from that depicted, in one or more embodiments. The numbers and spatial references used herein (e.g., "upper," "lower," "top," "bottom," etc.) are for convenience only and thus do not define the scope of protection or the scope of the embodiments. In this specification and in the appended claims, the expression that the tablets or dosage units described have a self-standing structure without a functional outer casing means that these tablets or units do not require an outer casing, such as a capsule or a flexible and permeable coating, for the extraction of a beverage (liquid coffee), i.e., they are designed to be inserted directly into the associated preparation machine. This, of course, does not exclude the fact that for marketing and storage purposes, the tablets or dosage units may be packaged in a suitable container, such as a bag, package, tray, etc.

[0017] The same reference numbers are used in the figures to indicate similar or technically equivalent elements.

[0018] Figures 1 and 2 show, for illustrative purposes, a coffee dosage unit or coffee tablet consisting of a compressed mass of coffee powder having a self-supporting structure without a functional casing (i.e., without a capsule body or casing body made of a flexible and permeable material).

[0019] In the example shown, tablet 1 has a substantially cylindrical central part 2 and two opposing end parts 3 and 4 with reduced diameter. Parts 3 and 4 each define, preferably flat, end faces 3a, 4a of tablet 1 and respective arcuate peripheries 3b, 4b for connection to the central part 2. This type of embodiment can be advantageous for pulling tablet 1 out of the associated mold during manufacture, as will be explained below.

[0020] However, other three-dimensional shapes for the tablet are not excluded. Preferred forms are those characterized by the geometry of rotation (including essentially toroidal or frustoconical shapes), which make it possible to obtain an optimal compression of the coffee powder in the method described below. In particular, these forms make it possible to maintain the equidistance of the peripheral surface of the tablet with respect to its core or center, which is particularly advantageous in the proposed method for reasons that will be explained below. Other possible shapes for the tablet are those distinguished by curved surfaces (for example, substantially spherical or ellipsoidal shapes).

[0021] Figure 3 represents, in the form of a schematic diagram, a possible sequence of operations of a method for the manufacture of a tablet according to the invention.

[0022] A represents the first stage and consists of obtaining the mass GC of roasted coffee beans. The second stage B, instead, represents a preferably homogeneous humidification phase of the mass GC to obtain the mass of wet coffee, i.e., coffee WGC having a predetermined moisture content. A purely illustrative example exemplifies the case of a horizontal screw mixer 10 arranged above a tank 11 that may be heated so that the resulting steam penetrates into the mixer 10 and then into the coffee powder. Humidification can also be carried out by spraying water (or other suitable aqueous solution) directly onto the powdered coffee GC, with or without subsequent mixing. According to one aspect of the invention, the predetermined moisture content is between approximately 3% and 11% by weight of the mass WGC, preferably between 4% and 6% by weight.

[0023] C represents the third stage, where the mass of wet coffee is fed to a dosing system 12, whereby a dose DGC of wet coffee powder is formed by at least one dosing nozzle 12a and fed into the corresponding cavity 13a of the molding tool, for example, a cavity at least partially defined by the lower mold part 13'. In a schematic example, the system 12 includes a plurality of dosing nozzles 12a for delivering a plurality of doses DGC to each cavity of the mold part 13'. However, the case of a single dosing nozzle that is controllable for delivering a dose DGC in a single lower cavity mold part or for the successive delivery of several doses DGC in each cavity of a multi-cavity mold part is not excluded from the scope of the invention. The dosing system 12 may be made by any technique known in the industry.

[0024] Stage D schematically represents the fourth stage, where each dose of the wet coffee DGC is compressed into each cavity 13a of the mold part 13', in particular through at least one corresponding upper mold part 13" having at least one punch that can be inserted into and slide within the cavity itself. The operating system 14 of the molding tools 13', 13" (e.g., of only the upper mold part 13") can be of any known design, preferably based on the use of at least one hydraulic cylinder. In various embodiments, together with the modularity of the pressure phase, the compression of the dose can be discontinuous, i.e., carried out with pressure and release phases, while modulating the pressure according to different types of profiles (pressure increase, pressure decrease, and / or various combinations thereof). This solution can be advantageous depending on the type of coffee used, its starting characteristics, and the desired sensory acceptance profile.

[0025] As can be seen, according to one aspect of the invention, at least two parts 13', 13" of the molding tool define the compression space or volume of the dose DCG, where the surfaces defining this space are heated in different ways. Also, in this case, in possible embodiments, the heating can be discontinuous, i.e., it can be carried out in different heating phases with temperature modulation according to the modularity of the heating phase and different types of profiles (temperature increase, temperature decrease, heating pause, and / or various combinations thereof). This solution can also be advantageous depending on the type of coffee used, its starting characteristics, and the desired sensory acceptance profile.

[0026] Thus, the compression can be carried out together with the simultaneous heating of at least two mold parts 13' and 13". In the case of heating with temperature modulation including a heating pause, part of the compression can be carried out in the absence of heating.

[0027] Stage E illustrates a subsequent stage of withdrawing each tablet 1 from the associated cavity of the forming tool, for example from the mold part 13'. The withdrawal may be carried out in any known manner, for example by using a system with a suction extraction element, or by providing a lower mold part 13' defined by a lower punch that can be slid upward so that the bottom of each cavity 13a itself lifts the tablet to a position outside the cavity. Alternatively, it can be provided to lift only the section of the lower mold part 13' or the section defining only the surrounding surface of the corresponding cavity 13a, whereby each tablet remains placed on the underlying stationary punch that defines the bottom of the cavity itself.

[0028] Regardless of the implementation of the mold and extraction method, the tablet 1 can then be placed on the conveyor system 15 for the purposes of subsequent operations. In a schematic example, a marking stage F is provided, during which a characteristic mark or identification code is defined in a known manner on the upper surface of the tablet 1. The marking can also be carried out by corresponding recessed or embossed imprints on each part of the mold. Following the marking stage F, a stage G of removing residual heat, for example via a suction system or using ventilation 17, can be carried out.

[0029] Thereafter, the packaging of the tablet 1 can be carried out. The tablet 1 can be individually or collectively packaged in a suitable container having suitable oxygen barrier properties, such as a bag, package, tray, tubular container. The tablet 1 may possibly be vacuum-packed in a suitable package.

[0030] As shown above, according to the present invention, the predetermined moisture content of the coffee powder introduced into the forming cavity of the table is, in a descriptive manner, between 3 and 11% by weight of the corresponding dose, preferably between 4 and 6% by weight. According to a further aspect of the present invention, the intermediate region of the compression space has a temperature different from at least one of the lower and upper regions of the compression space while the dose of wet coffee required for the formation of the tablet is subjected to compression. Preferably: - The aforementioned intermediate region is defined by the corresponding part of the peripheral surface of the forming cavity; - The lower region is defined by the bottom surface of the forming cavity which may belong to the lower punch; and - The upper region is defined by the surface of the upper punch driven to actively compress the dose of wet coffee DGC.

[0031] In various embodiments, the forming arrangement or apparatus used for the implementation of the present invention comprises at least two mold parts, which are configured to compress the dose of wet coffee between them within the corresponding forming cavity, and the at least two mold parts define the bottom surface, the head surface, and the peripheral surface of the said cavity.

[0032] Figure 4 shows, for illustrative purposes only, a possible apparatus that can be used for the mold of a coffee tablet according to the present invention, generally designated by 13, which basically includes two mold parts. In this figure, 19 shows the base on which the lower mold part 13' is placed, which is here obtained by two overlapping sections shown by 20 and 21, preferably formed of a heat-conductive material such as a metal material, for example stainless steel. As shown in Figure 5 (where the mold 13 is shown in cross-section in the closed position), the lower section 20 defines, or is associated with, a series of punches 35 that are here substantially cylindrical in shape, and each of the series of punches 35 is inserted into the respective through-cavity 22 of the upper mold section 21, which is here also substantially cylindrical in shape. In the example, the lower mold part 13' has nine forming imprints, each of which is defined by the cavity 22 and the corresponding lower punch 35, although of course the number of cavities may be different. In the example, it is assumed that the sections 20 and 21 of the mold part 13 are stationary and the extraction of the tablet 1 from the forming cavity 22 is performed by a gripper / lifting system that operates by suction. By the way, in other embodiments, the sections 20 and 21 of the mold may be mold parts separable by the extraction of different types of tablets.

[0033] Referring again to Figures 4 and 5, 13" shows the upper mold part, which may be connected to the corresponding operating system 14 and may have two overlapping sections 30 and 31, although this is not an essential feature. From the lower surface of the section 31, a series of upper punches 32, which are here substantially cylindrical in shape, project by a number corresponding to the number of cavities 22 of the lower mold part 13'. Again, from the lower surface of the section 31 of the mold part 13", a series of positioning and guide pins 33 project for insertion into the respective positioning and guide paths 23 provided in the section 21 of the lower mold part 13'.

[0034] The opposing surfaces of punches 32 and 35, in the example, respectively realize the bottom surface and the head surface of the molding cavity. FIG. 5 shows, in various preferred embodiments, how the opposing surfaces of the above-mentioned punches 32 and 35 define respective shaped surfaces or imprints 32a and 35a intended to give corresponding shapes to the two end faces of the tablet, for example, the shapes of portions 3 and 4 of tablet 1 shown in FIGS. 1 and 2. Here, a limited portion of the cylindrical surface of cavity 22 defined in mold part 13' (shown as 22a in FIG. 6) is instead intended to define the peripheral profile of the intermediate portion of tablet 1.

[0035] With mold 13 in the closed position as shown in FIG. 5, each cavity 22 and corresponding lower punch 35 and upper punch 32 define a compression space or volume for the dosing of wet coffee, and this compression space is: - an intermediate region defined by a corresponding portion of the peripheral surface of cavity 22, - a lower region defined by the shaped surface 35a of lower punch 32, and an upper region defined by the shaped surface 32a of upper punch 32.

[0036] The compression space or volume is shown as CS in FIG. 6, and its intermediate, lower, and upper regions are shown as CSi, CSb, and CSt, respectively, in the same figure. 22a shows the aforementioned portion of the cylindrical surface of cavity 22 that identifies the intermediate region CSi.

[0037] As described above, at least during the compression phase of the dose of wet coffee DGC aimed at obtaining tablet 1, the intermediate region Csi of the compression space CS has a temperature different from, preferably lower than, at least one of the lower region CSb and the upper region CSt. In various preferred embodiments, both the lower region CSb and the upper region CSt are at a higher temperature than the temperature of the intermediate region CSI, although in some cases the intermediate and lower regions may be at the same temperature. In various preferred embodiments, the upper end region CSt is at a higher temperature than the lower end region CSb.

[0038] Generally, tests carried out by the applicant have made it possible to confirm that the preferred temperatures are as follows: - Upper end region CSt: between 55 and 100 °C; - Intermediate region CSI: between 40 and 95 °C; and - Lower end region CSb: between 50 and 95 °C.

[0039] The applicant has noticed that by the controlled heating of the lateral face 22a of the compression space CS, the problem of rebound phenomenon, i.e., the formation of side cracks in the tablet associated with a kind of springiness of the mass under compression that occurs upon release of the compression, is significantly reduced. Surprisingly, the controlled heating of the lateral face of the compression space has led to a significant reduction in the springiness effect, even compared to the "cold" forming of compressed tablets at a pressure higher by more than twice and over a time period twice as long. Thanks to the reduction of the springiness effect, in various embodiments, it is also possible to plan the heating and compression of the dose in successive phases, with modulation of the parameters or modular management of the phases to adapt the process to different types of coffee and different sensory acceptance profiles.

[0040] Therefore, the proposed solution of selective heating of the mold effectively solves the problem of the formation of transverse cracks in the tablet and also allows for a reduction in the compression time, which is advantageous for productivity, especially in the case of the use of multi-cavity molds.

[0041] This advantageous effect is thought to be related to the fact that the use of low temperatures in the intermediate region Csi of the compression space makes it possible to limit the evaporation of water from the intermediate part 2 of the tablet 1. On the other hand, the use of high temperatures in the upper region CSt has the effect of compensating for the shorter contact time between the upper punch 32 and the coffee dose DGC compared to the intermediate region Csi and the lower region CSb.

[0042] In any case, heating of the entire mass of coffee according to a controlled temperature gradient between the surface zone and the central zone of the tablet is obtained, whereby in this central region it is possible to reach the temperature required for the agglomeration process (especially in relation to so-called solidification), which in the indicative method is between 40 and 60 °C, especially included around 50 °C.

[0043] Thermographic analysis of the tablet during the forming phase confirmed an effective distribution of temperature by a profile with a gradient according to the zone, and the central zone of the tablet was advantageously maintained at a low temperature and its sensory acceptance profile was preserved.

[0044] In various embodiments, selective heating in the various regions or surfaces of the space CS is obtained by providing suitable heating means in different parts of the mold. In various embodiments, the mold part comprises means for heating the head surface of the forming cavity, while other mold parts are provided with means for heating the bottom surface of the forming cavity and at least some part of its peripheral surface.

[0045] In the case illustrated in FIGS. 4 and 5, a mold part 13" movable for the purpose of an electric resistance 31a is provided with the intention of heating the punches 32, in particular their lower faces 32a. In the example, the resistances 31a can be arranged in the section 31 of the mold part 13" from which the punches 32 project, and the resistances 31a each extend in length at positions corresponding to each row of punches 32 (three punches 32 in the illustrated case). In this type of embodiment, heat transfer is effected essentially by conduction between the section 31, which is essentially in the form of a plate, and the punches 32. For this purpose, the section 31 and the punches 32 are preferably made of a heat-conductive material, preferably a metallic material, such as stainless steel.

[0046] In various embodiments, a substantially similar heating arrangement is provided for heating the lower punches 35 as well, and thus a plurality of electric resistances 20a are arranged in the section 20 of the mold part 13', each resistance 20a extending in length in each row of punches 35 (three punches 35 in the illustrated case). Also in this case, heating of the punches 35, and in particular their upper surfaces 35a, and heat transfer are effected by conduction between the section 20, which is essentially in the form of a plate, and the punches 35. Similar to the mold part 13", the section 20 and the punches 35 are preferably made of a heat-conductive material, preferably a metallic material, such as stainless steel.

[0047] Similar heating resistances can be used to heat the cavities 22 of the section 21 of the mold part 13', in particular the corresponding parts of the surfaces 22a defining the compression space Cs. In the illustrated case, the section 21, also preferably made of a heat-conductive metallic material, such as stainless steel, has two series of electric resistances 21a and 21b, which also extend longitudinally.

[0048] In various embodiments, resistors 21a and 21b are arranged obliquely at different heights within section 21 (see, for example, FIG. 5). Thus, with such an arrangement, resistors 21a and 21b form a kind of grid structure in which each cavity 22 is heated by respective portions of at least two different intersecting resistors 21a and 21b. In a non-limiting example, two resistors 21a and two resistors 21b are provided such that a continuous series of cavities closest to the outer peripheral profile of section 21 are subjected to slightly lower conductive heat compared to the section closest to the electrical resistance. In principle, there is nothing preventing the provision of four resistors 21a and four resistors 21b, and thus, in the above-mentioned portions of the cavities closest to the outer peripheral profile of section 21, respective portions of resistors 21a or 21b extend. However, the applicant has found that, in practice, and with reference to the exemplary case of a 9-cavity mold 22, the use of only four resistors 21a and 21b does not significantly affect the forming quality, and in particular simplifies the realization of section 21 and allows for a reduction in its weight and overall dimensions. The various sections 20, 21, and 31 provided with resistors are equipped with suitable temperature sensors, for example in the form of thermocouples, for the detection and control of the temperature of surfaces 22a, 31a, and 35a in accordance with process requirements. The operation of the resistors is preferably managed by a control system (not shown) according to signals obtained via temperature sensor means. The use of electrical resistance is advantageous in terms of temperature control, but in possible alternative embodiments, they may be replaced by conduits through which a suitable heating fluid, for example water, flows.

[0049] In other embodiments, the heating resistors can be arranged vertically and each can extend into the region included between four adjacent cavities. Another possibility is to provide the heating resistors, for example arranged vertically, inside each punch 35 (however, this involves a greater vertical load on the corresponding mold part).

[0050] In a general sense, the temperature selected for the various regions of the compression space CS, as well as the corresponding initial humidity values of the coffee powder (in any case between 3 and 11% by weight) and the diameter of the tablets (preferably variable between 3.5 and 5.5 cm in the descriptive method) depend on the following variables: a) The type and roasting color of the coffee; b) The particle size of the coffee powder; c) The x50 / powder ratio; d) The amount of coffee powder in a single dose; e) The thickness of the tablets; f) The compression time of the coffee powder dose; g) The force and compression profile presented to the coffee powder dose; h) The desired residual moisture value of the tablets; i) The desired density of the tablets; l) The desired mass loss. The variables that gave satisfactory results in the tests conducted by the applicant are as follows: a) The type and roasting color of the coffee: Arabica, Robusta, Arabica / Robusta blend with a roasting color of 25 to 65°N. b) Particle size analysis: 200 to 700 μm, preferably between 270 and 450 μm for espresso coffee and between 350 and 550 μm for filter coffee. c) The x50 / powder ratio: 15 to 25 μm for espresso coffee and 20 to 35 μm for filter coffee. d) Amount: 4 g to 20 g, preferably 4 to 11 g for espresso and 6 to 20 g for filter coffee. e) Thickness: 5 mm to 25 mm, preferably 5 to 20 for espresso and 8 to 25 for filter coffee. f) Compression time: Maximum 180 seconds. g) Compression force and profile: Maximum 17 kN per cavity, preferably between 7 and 8.5 kN. h) Residual moisture value: 2 to 5%. i) Desired density: Between 0.4 and 0.9 g / cm 3 preferably between 0.5 and 0.6 g / cm3 Among. l) Desired mass loss: less than 5%.

[0051] As described in connection with FIGS. 1 and 2, in a preferred embodiment, the tablet 1 obtained by the process according to the invention does not have a strictly cylindrical shape, but instead has a shape characterized by a substantially cylindrical central part 2 and two shaped end parts 3 and 4, where parts 3 and 4 each define the following: - Preferably flat, end faces 3a, 4a of the tablet 1 having a diameter smaller than that of the central part 2, and - Arcuate peripheral parts 3b, 4b for connection to the central part 2.

[0052] From this point of view, FIGS. 7, 8, and 9 represent possible imprints 32a of the punch 32, preferably corresponding to the bottom of the forming cavity (which bottom is represented in a given example by a punch 35 having a corresponding imprint 35a). By the profile shown, it is possible to obtain a tablet shape of the type shown in FIGS. 1 and 2, and surfaces I and II are intended to define the end faces (3a, 4a) and the connecting surfaces (3b, 4b) of the tablet, respectively.

[0053] When the radius of surface II is substantially equal to or close to 90°, the imprint in FIG. 7 is particularly advantageous for removing breakage during removal of the tablet from the mold and mass loss in the same tablet. However, this shape suggests that torsional forces are applied to them for the purpose of lifting the tablets (especially from the lower punch). This makes the process more complex and can cause dust during extraction from the mold.

[0054] When the radius of surface II is more relaxed (close to 45°, included in the range of 30° to 60° in any case), the imprints mentioned in FIGS. 8 and 9 allow for easier extraction of the tablets without the need for torsion (and thus without dust) and without substantially determining the formation of transverse cracks.

[0055] The profiles referred to in FIGS. 7 to 9 were subjected to comparative tests by the applicant together with a substantially completely cylindrical compression profile. The test conditions were as follows: Starting coffee powder having a moisture content between -5.3 and 5.7% -x50 / powder ratio = 324 μm / 18.79% -Surface temperatures 32a, 22a, 35a: 85 / 80 / 80 ° -Compression time: 30 seconds.

[0056] Compared to the shapes obtained with the profiles of FIGS. 7 to 9, the cylindrical shape showed a much greater mass loss in the tablets (1.07% vs. 0.56%, 0.66%, and 0.71%), and in particular, the formation of transverse cracks at a rate of more than 50%. FIG. 10 shows a photographic image representing the results of the comparative tests. In this figure, part A) relates to a completely cylindrical tablet, while parts B), C), and D) relate to the tablets obtained from the final profiles of FIGS. 7, 8, and 9, respectively.

[0057] From the given description, the characteristics and advantages of the present invention are apparent. The proposed solution enables the rapid and easy production of tablets for the extraction of beverages starting from the powder of roasted coffee beans, and the problem of the formation of transverse cracks in the tablets is eliminated or significantly reduced in any case.

[0058] It will be apparent to those skilled in the art that numerous variations are possible without departing from the scope of the invention as defined by the claims below.

[0059] For example, it should be noted that one or more parts of the process (e.g., one or more of phases C to F in FIG. 2) can be carried out in a nitrogen environment.

[0060] In a possible variant embodiment, a part of the coffee mass intended to make tablets may contain a smaller fraction of soluble coffee, which may be homogeneously mixed with the roasted coffee beans, or restricted to the central region of the tablet, or otherwise may be layered within the tablet.

[0061] The practical realization of the forming tool may differ from that illustrated in the figures without impairing the provision of heating means or elements designed to heat at least some part of the peripheral surface of the forming cavity in a different manner with respect to at least one of the bottom surface and the head surface of the same cavity. For example, the mold may comprise at least three parts as follows: - An intermediate part having through holes for defining the peripheral surface of the forming cavity and provided with heating means designed to heat at least some part of its peripheral surface (in particular, that part which laterally defines the compression space or volume of the coffee powder dose), - A lower part defining the lower punch, the proximal end of which defines the bottom surface of the compression space or volume and provided with heating means designed to heat said bottom surface, and An upper part defining the upper punch, the proximal end of which defines the head surface of the compression space or volume and provided with heating means designed to heat said head surface.

[0062] In an embodiment of this type, the intermediate part of the mold may be stationary, and the lower and upper mold parts may be movable for compressing the coffee dose.

[0063] Another possibility is to provide the mold in two parts, each of which defines a respective end face (head surface or bottom surface) and a respective part of the peripheral surface of the compression space or volume. In this case, each mold part will be provided with means designed to heat its respective end face and respective part of the peripheral surface. In an embodiment of this type, one or both of the mold parts may be movable for compressing the coffee dose between them.

Claims

1. A method for manufacturing a coffee tablet or similar coffee dosing unit having a self - supporting structure without a functional outer casing, comprising: i) providing a wet weight of roasted coffee beans having a moisture content between 3% and 11%, preferably between 4% and 6%; ii) feeding said wet weight to a dosing device to obtain a dose of wet coffee; iii) placing the dose of wet coffee into a cavity of a forming tool, said cavity having a bottom surface, a head surface, and a peripheral surface, at least one portion of said bottom surface, said head surface, and said peripheral surface being configured to define a compression space for the dose of wet coffee; iv) compressing the dose of wet coffee within said cavity to form a coffee tablet; v) withdrawing the coffee tablet from said cavity and, step iv) comprises compressing the dose of wet coffee while one portion of the peripheral surface is heated at a different temperature, preferably at a temperature lower than the temperature at which at least one of the bottom surface and the head surface is heated. Method.

2. The method according to claim 1, wherein both the bottom surface and the head surface are at a temperature higher than the temperature of said portion of the peripheral surface.

3. The method according to claim 2, wherein the head surface is at a higher temperature than the bottom surface.

4. - the head surface is at a temperature comprised between 55 and 100 °C; - the portion of the peripheral surface is at a temperature comprised between 40 and 95 °C; and the bottom surface is at a temperature comprised between 50 and 95 °C The method according to any one of claims 1 to 3.

5. The method according to any one of claims 1 to 3, wherein the roasted coffee beans have a particle size between 200 and 700 μm, preferably between 270 and 450 μm in the case of espresso coffee, or between 350 and 550 μm in the case of filter coffee.

6. The coffee tablet has: - a thickness between 5 and 20 mm when provided for the preparation of espresso coffee; - a thickness between 8 and 25 mm when provided for the preparation of filter coffee; The coffee tablet preferably has a diameter between 3.5 and 5.5 cm The method according to any one of claims 1 to 3.

7. The dose of wet coffee is: When the coffee tablet is intended for the preparation of espresso coffee, it is between 4 and 11 g, When the coffee tablet is intended for the preparation of filter coffee, it is between 6 and 20 g The method according to any one of claims 1 to 3, having a weight of.

8. The method according to any one of claims 1 to 3, wherein the dose of the wet coffee is compressed over a time not exceeding 180 seconds.

9. The method according to any one of claims 1 to 3, wherein the dose of the wet coffee is compressed with a compressive force not exceeding 17 kN, preferably between 7 and 8.5 kN.

10. Step iv) is: Providing a mold part having at least one punch having a punch surface defining one of the head surface and the bottom surface; Inserting the punch into a part of the cavity defined by a further mold part in such a way that compression of the dose of the wet coffee is caused by the punch surface; Pulling the punch out of the cavity The method according to any one of claims 1 to 3, comprising.

11. A coffee tablet or similar coffee dosing unit having a self-supporting structure without a functional outer casing, obtainable by the method according to any one of claims 1 to 3, wherein the coffee tablet is based on a powder of roasted coffee beans having a particle size between 200 and 700 μm, and the coffee tablet is: - Weighing between 4 and 20 grams; - Diameter between 3.5 and 5.5 cm; - Thickness between 5 mm and 25 mm; - Residual moisture content between 2 and 5%; -0.4 to 0.9 g / cm ３ of density A coffee tablet or similar coffee dosing unit having.

12. The coffee tablet according to claim 11, having a body having at least partially a substantially cylindrical shape, or having a substantially rotational geometry.

13. The coffee tablet according to claim 12, wherein the body of the coffee tablet has a substantially cylindrical central part and two opposing end parts each defining an end face and an arcuate peripheral surface connecting to the central part.

14. A system for the manufacture of a coffee tablet or similar coffee dosing unit having a self-supporting structure without a functional outer casing, the system comprising a supply arrangement, a dosing arrangement, and a shaping arrangement, The supply arrangement is designed to supply the wet weight of roasted coffee beans to the dosing arrangement, The dosing arrangement is designed to place a dose of wet roasted coffee beans into a corresponding cavity of the shaping arrangement, The shaping arrangement has at least two mold parts designed to compress a dose of the wet roasted coffee beans within the cavity, the at least two mold parts defining a bottom surface, a head surface, and a peripheral surface of the cavity, The bottom surface, the head surface, and corresponding portions of the peripheral surface define a compression space for a dose of the wet roasted coffee beans therebetween, The shaping arrangement has controllable heating means for heating the portions of the peripheral surface in different manners with respect to at least one of the bottom surface and the head surface, system. **Claim 15** The system according to claim 14, wherein the at least two mold parts are controllable to compress a dose of the wet roasted coffee beans and, simultaneously, to heat the portions of the peripheral surface at a temperature different from, preferably lower than, the temperature at which at least one of the bottom surface and the head surface is heated. **Claim 16** The system according to claim 14 or claim 15, wherein the portions of the peripheral surface, the bottom surface, and the head surface are at least partially substantially cylindrical or shaped to give the coffee tablet a shape having a substantially rotational geometry. **Claim 17** The system according to claim 16, wherein the portions of the peripheral surface, the bottom surface, and the head surface are shaped to give the coffee tablet a shape having a central portion that is substantially cylindrical and two opposing end portions each defining an end face and an arcuate peripheral surface connecting to the central portion. **Claim 18** The system according to claim 14 or claim 15, wherein the heating means has an electrical resistance. **Claim 19** The shaping arrangement has at least: - a first mold part defining at least the portion of the peripheral surface of the cavity; - a second mold part having at least one punch insertable into the cavity of the first mold part, the punch having a corresponding punch surface defining one of the head surface and the bottom surface, and has At least the second mold part is displaceable relative to the first mold part for compressing a dose of the wet roasted coffee beans into the cavity via the at least one punch The system according to claim 14 or claim 15 **Claim 20** The system according to claim 14 or claim 15, comprising an extraction arrangement configured to obtain extraction of the coffee tablet from the cavity of the forming arrangement

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