HK1188548B - Brewing device for creating a coffee beverage and method for creating a coffee beverage by means of a brewing device - Google Patents

Abstract

The brewing device (10) for creating a coffee beverage has a brewing unit (11) having a brewing chamber (12) for brewing coffee, a crema unit (21) for creating a crema having a crema chamber (200) connected to the brewing chamber (11) by means of a coffee passage (214) and having a valve piston (201) for opening and/or closing the coffee passage (214), which valve piston can be moved in the crema chamber (200) relative to the coffee passage (214), and an outlet opening (31) for the particular coffee beverage, wherein the crema unit (21) is connected to the outlet opening (31) by means of an outlet line (30) in such a way that, in order to create the particular coffee beverage, coffee brewed in the brewing unit (11) during a brewing process can flow through the coffee passage (214) and the crema chamber and reach the outlet opening (31). The valve piston (201) can be moved in such a way that the valve piston can be brought into a plurality of different specified movement positions relative to the coffee passage (214), wherein different consecutive brewing processes for creating different coffee beverages can be realized in such a way that, for one of the particular brewing processes, the valve piston (201) assumes a specified movement position different than the specified movement position for a different brewing process, and wherein the crema unit (21) is designed in such a way that the coffee brewed during the particular brewing process can be swirled through at different intensity depending on the particular specified movement position of the valve piston (201).

Description

Brewing device for producing a coffee beverage and method for producing a coffee beverage using a brewing device

The invention relates to an infusion device for producing a coffee beverage, having a crema unit arranged in a coffee outlet, with which crema can be produced. The invention further relates to a method for producing a coffee beverage using such an infusion device.

In particular, the present invention relates to a brewing device having a crema unit of specific structure, by means of which the quantity of crema produced in each brewing operation can be varied.

For example, a brewing device with an option to increase the amount of crema produced in a brewing operation is known from EP2168465a 1. The brewing device described herein is equipped with a so-called crema valve which is arranged between the brewing unit and the coffee outlet and limits the outflow of the brewed coffee in the brewing device through a compression spring-loaded stopper into the coffee outlet tube. Due to the fact that the brewed coffee is pressed under a certain pressure in the direction of the stop, the compression spring exposes an annular gap through which the brewed coffee can flow into the delivery duct, provided that the pressure of the brewing water is sufficiently high. Due to the fact that the size of the annular gap is limited, a disturbance is generated when the brewed coffee passes. This swirling flow of the brewed coffee causes a fine-pored foam called crema to be created.

In order to be able to increase the amount of crema made in this way, conventional brewing devices comprise a gas injector with which a variable amount of gas at variable pressure can be introduced into the crema chamber. Due to this additional swirling passage of the coffee in the crema chamber, i.e. after passing the annular gap, the amount of crema made in the conventional brewing device increases. Thus, although it is possible to artificially increase the amount of traditionally made crema by introducing gas into the crema chamber by means of a traditional brewing device, there is no measure to minimize the amount of specifically made crema.

Furthermore, due to the very different coffee cultures of the regions and the different coffee beverages resulting therefrom, such as cappuccino, latte macchiato, espresso, there are different individual tastes, wherein there is also a desire regarding the amount of crema and the pore size to make smaller or larger pore sizes of crema until a coffee beverage without any crema layer is output by the brewing device.

Due to the use of compression spring loaded valves in conventional brewing devices, there is also a risk of beverage residue accumulating on the valve, causing it to become somewhat clogged, wherein smooth operation of the valve is affected. The compression spring-loaded valve may in some cases resist the ever-increasing pressure of the brewing water before it exposes the annular gap of the passageway for the brewed coffee beverage. Although this may lead to a change in crema concentration, in the worst case this blockage causes the valve to release suddenly at a sufficiently high brewing water pressure and open sharply against the restoring force of the spring. Since coffee is likewise suddenly present in the coffee spout, it may happen that, for example, coffee is squirted out of the spout at an excessive initial pressure, resulting in an unsatisfactory coffee beverage.

Another disadvantage of conventional brewing devices is that, due to the spring-loaded crema valve, during stoppage of the brewing device, i.e. for example after completion of a brewing operation, any coffee water remaining in the coffee outlet duct accumulates behind the crema valve and cannot return to the brewing chamber. When another brewing operation is subsequently carried out, this residual liquid is first delivered at the coffee outlet before the freshly brewed coffee reaches the coffee outlet. In the case of long periods of stagnation between successive brewing operations, it is then possible that this residual liquid cools to such an extent that it has a negative effect on the temperature of the delivered coffee beverage.

The present invention is based on the need to avoid the above-mentioned drawbacks and to propose an infusion device for making coffee beverages and a method that make it possible to vary the quantity of crema made accordingly over a wide range and to avoid the abrupt opening of the crema valve. Furthermore, the temperature of the output coffee should remain substantially constant even for long periods of standstill of the brewing device.

This need is met by a brewing device and a method. The infusion device for making a coffee beverage according to the invention comprises: a brewing unit having a brewing chamber for brewing coffee; a crema unit for making crema having a crema chamber connected to the infusion chamber via a coffee passage and a valve piston movable within the crema chamber relative to the coffee passage to open and/or close the coffee passage; and an outlet opening for a particular coffee beverage, wherein the crema unit is connected to the outlet opening by an outlet tube, such that coffee brewed in the brewing unit can flow through the coffee passage and the crema chamber and can reach the outlet opening for making the respective coffee beverage.

According to the invention, the valve piston can be moved in such a way that it can be brought into a plurality of different designated movement positions relative to the coffee passage, wherein different successive brewing operations for making different coffee beverages can be realized in such a way that, for one particular brewing operation, the valve piston assumes a designated movement position which is different from the designated movement position for the different brewing operation, and wherein the crema unit is designed in such a way that the coffee brewed in the crema chamber during a particular brewing operation can be swirled through with different intensities depending on the particular designated movement position of the valve piston.

The first designated movement position of the valve piston may for example be chosen such that the valve piston tightly closes the coffee passage, thereby preventing liquid from flowing from the brewing chamber into the crema chamber.

In this case, the brewing water may be directed into the brewing chamber and placed under pressure, for example, so that coffee may be brewed within the brewing chamber at a relatively high pressure of the brewing water. In this case, for example, the brewing device allows the preparation of a coffee beverage in the form of espresso coffee. Other specified positions of movement of the valve piston may be selected such that the valve piston assumes different specified distances from the opening of the coffee passage into the crema chamber.

The brewing device allows the valve piston to be positioned in respective different designated movement positions for different successive brewing operations (for making different coffee beverages) or allows the valve piston to be moved between different designated movement positions during a brewing operation. The particular position of movement assumed by the valve piston during a brewing operation affects the amount of pressure of the brewed water within the brewing chamber during the brewing operation (hereinafter referred to as "brewing water pressure") and the speed at which the brewed coffee within the brewing chamber flows through the coffee passage into the crema chamber and then through the outlet tube, and thus also affects the flow rate of the brewed coffee within the coffee passage or outlet tube.

Since the path of movement of the valve piston (e.g. by simulating the insertion depth of the valve piston into the crema chamber and the further contact pressure of the valve piston against the coffee passage) may be varied, the intensity of the swirling passage of coffee pressed through the coffee passage may be varied with respect to the brewing operation of the coffee beverage. By varying the intensity of the swirling flow, the amount of crema and pore size can be varied over a wide range.

If, for example, the particular position of movement of the valve piston during the brewing operation is selected such that coffee is brewed in the brewing chamber at a relatively high brewing water pressure and coffee flows into the crema chamber at a relatively high velocity, the brewed coffee swirls through within the crema chamber with a relatively high intensity, with the result that such a coffee beverage (e.g., espresso) is produced: there is a relatively large amount of crema on coffee beverages. On the other hand, if the particular position of movement of the valve piston during the brewing operation is selected such that coffee is brewed within the brewing chamber at a relatively low brewing water pressure and coffee flows into the crema chamber at a relatively low velocity, the brewed coffee swirls through within the crema chamber at a relatively low intensity or not at all, with the result that a coffee beverage without crema (e.g., a coffee beverage with a filtered coffee strength) or a coffee beverage with a relatively small amount of crema thereon is produced. Thus, the brewing device according to the present invention can be used to make different coffee beverages of different strengths and with different amounts of crema on a particular coffee beverage.

Another advantage of the solution according to the invention, as compared to conventional prior art brewing devices, is seen in the fact that, thanks to the valve piston moving or displacing in a variable manner, i.e. independently of (conventional brewing devices rely on) the interaction between the brewing water pressure acting on the valve piston and the return force of the spring acting on the valve piston, the coffee passage can be opened even after the completion of the brewing operation, so that any residual liquid in the crema chamber or in the outlet duct can flow back into the brewing chamber after the brewing operation. The residual liquid may then be directed into a residual water container (such as a drip tray). In this way, a decrease in the coffee output temperature for the next brewing operation is avoided.

Finally, it is advantageous that, since the valve piston is moved or displaced in a controlled manner, sudden retraction of the valve can be avoided, for example, even if the valve is clogged by coffee residues.

An embodiment of the brewing device according to the invention is characterized in that the brewing device further comprises a control unit and a final control element. The final control element is coupled to the movable valve piston and is adapted to vary the position of movement or depth of insertion of the valve piston within the crema chamber. The final control element receives a control signal from the control unit, wherein the control signal issued by the control unit corresponds to, for example, a target position of the valve piston, i.e. one of the specified movement positions of the valve piston. In this way, the concentration of crema made in a wide range and particularly finely can be varied.

A control unit designed as a regulator is also provided and the brewing device further comprises a set point setting unit and a sensor. The sensor records the measured variable and supplies the measured variable as a measurement signal to the regulator, wherein the regulator is configured such that the set point specified by the set point setting unit is obtained by moving or displacing the valve piston.

Further, due to the configuration as a regulator, it is possible to specify not a static set point but a set point stage number (setpointprogress) that changes with time. This allows to vary the concentration of crema produced in a wide range.

The sensor may be configured as, for example, a pressure sensor that records the pressure within the brewing chamber via a suitable arrangement. By appropriate construction of the regulator receiving pressure readings from such a pressure sensor, the displacement path of the valve piston can be adjusted so that, for example, a specified static pressure (which is specified over time in the form of a static pressure set point) rises within the brewing chamber. Of course, alternatively, a pressure set point can be specified that varies over time as the brewing operation progresses, such that a (passthrough) pressure gradient is passed by the regulator during the brewing operation.

Furthermore, the sensor can be designed as a position sensor, wherein such a sensor is mounted such that it can detect the instantaneous movement position of the valve piston. The kinematic position set point here may be specified as also being static over time or varying over time.

A particular advantage in this case is that the instantaneous pressure of the infusion water in the infusion chamber and the instantaneous movement position of the valve piston can be measured very precisely by means of different sensors, which, for respective specified set points, ensure an extremely reproducible crema concentration on the coffee beverage of a particular output.

The final control element can be designed, for example, as an electromechanical drive (for example as a stepping motor), which allows particularly simple control of the movement position of the valve piston.

In addition, the provision of the crema unit and the final control element arranged inside the infusion piston of the infusion device has the particular advantage that the overall volume of the infusion device is not enlarged by the design according to the invention compared with conventional devices.

Alternatively, the crema unit together with the final control element may be designed as a separate assembly, which may be arranged spatially separate from the infusion unit. In this case, the crema unit may be connected to the infusion unit by a duct or tube. For this purpose, the distance between the outlet opening of the brewing chamber for the respective brewed coffee and the coffee passage of the crema chamber may be bridged by a respective duct or a respective tube, so that the respective brewed coffee may flow from the brewing chamber into the crema chamber via the respective duct or the respective tube. The outlet aperture of the brewing chamber may, for example, be formed within the brewing piston, and one end of a respective tube or a respective tube may be attached to the brewing piston. Due to the fact that the crema unit together with the final control element is designed as a separate assembly, the crema unit can be (arbitrarily) positioned independently of the brewing unit. The advantage is that the crema unit can be retrofitted to existing brewing units even if there is not enough space within the brewing unit to integrate the crema unit and the final control element.

It is provided and possible that the set point generated by means of the set point setting unit is specified by a stored crema profile. In a coffee machine housing a brewing device according to the invention, this profile can be integrated with, for example, an automatic control system and associated with a predetermined characteristic of the crema. By selecting the respective profile, it is thus possible for the coffee beverage to be delivered to form crema on the basis of the automatically set setpoint value, which crema then has certain desired properties. This makes it possible to automatically vary, in a particularly advantageous manner, the quantity and/or the characteristics of the crema (for example the strength and/or the taste of the crema) in a single brewing operation, over a wide range, for example according to the preferences of the user.

Typically, a coffee sieve is provided, arranged in the coffee passage or between the crema unit and the infusion chamber, which prevents the passage of ground coffee into the crema chamber. According to the invention, the coffee sieve can be washed by liquid flowing back into the infusion chamber at the end of the infusion operation and after moving the valve piston into a position in which it is possible to leave liquid in the outlet duct to flow back into the infusion chamber, so that very little coffee residues remain in the coffee sieve after the infusion operation.

Exemplary embodiments of a brewing device for making a coffee beverage according to the invention and of a method according to the invention will now be explained in detail with the aid of the accompanying drawings, in which:

figure 1 shows a schematic view of a brewing device according to the invention with a brewing unit and a crema unit;

FIG. 2 shows a schematic circuit diagram of the measuring, control and regulating components of the device according to the invention;

figure 3 shows a transverse cross-section of the infusion unit with the crema unit and the stepper motor according to figure 1;

figure 4 shows another transverse cross-section of the infusion unit with the crema unit and the pressure sensor according to figure 1;

figure 5 shows a schematic view of a brewing device according to the invention similar to that of figure 1, but with a sensor in another embodiment configured as a position sensor and integral with the final control element and the valve piston partially removed from the crema unit;

fig. 6 shows a schematic view of the crema unit and the final control element according to fig. 1 together forming a separate assembly which can be arranged spatially separate from the infusion unit of the infusion device.

Fig. 1 shows a schematic view of a brewing device 10 for producing a coffee beverage according to the present invention. In the figure, the brewing device 10 comprises a coffee container 35 from which coffee, for example in powder form, is automatically taken and supplied to the brewing chamber 12 of the brewing unit 11 via a coffee feed tube 36. The brewing chamber 12 of the brewing unit 11 is further connected to a water tank 32 managing a supply of fresh water via a water supply pipe 33. The infusion chamber 12 further comprises an outlet aperture 12-1 for the particular infused coffee. At the outlet aperture 12-1 of the brewing chamber 12, a crema unit 21 is arranged, which comprises a crema chamber 200 and a valve piston 201 extending into the crema chamber 200. The valve piston 201 comprises a stop 202 arranged at the end of the valve piston 201 facing the brewing chamber 12. The valve piston 201 is configured to be movable in its longitudinal direction when positioned in a plurality of different specific positions (hereinafter referred to as "movement positions").

In one of the particular positions (shown in fig. 1), the stopper 202 closes a coffee passage 214 connecting the brewing chamber 12 with the crema chamber 200, wherein the coffee passage 214 opens into the brewing chamber 12 at the outlet aperture 12-1. Furthermore, in its longitudinal direction, the valve piston 201 is movable in a direction away from the brewing chamber 12 (upwards in fig. 1), so that the valve piston 201 can assume one or more other specific positions of movement (not shown in fig. 1), in which positions the valve piston 201 is arranged at a distance from the coffee passage 214, so that the stopper 202 no longer closes the coffee passage 214 and the brewed coffee from the brewing chamber 12 can flow into the crema chamber 200 as desired. The coffee is brewed, after swirling through as desired, flows into the crema chamber 200 and is there, in the upper region, directed through the outlet duct 30 towards the outlet aperture 31. The valve piston 201 is movable by means of the final control element 211 such that its insertion depth into the crema chamber 200 can be varied within wide limits.

The stopper 202 may be made of rubber or similar elastic material, for example, and serves to change the contact pressure towards the lower chamber end of the crema chamber 200 by means of the final control element 211. In this way, by varying the contact pressure or possibly by further lifting the valve piston 201, the gap formed between the stopper 202 and the coffee passage 214 may be varied when the valve piston 201 is moved from the movement position shown in fig. 1 to allow coffee to enter the crema chamber 200 from the brewing chamber 12, such that the brewed coffee entering the crema chamber 200 through this gap comprises crema, as regards its condition (e.g. strength or taste) and/or the amount of a particular crema made (depending on the particular movement position of the valve piston 201) is variable (variable). By moving the valve piston 201 on one side of the final control element in the direction of its end 204, the amount of crema produced can be reduced to a minimum.

In the illustrated embodiment, a sensor 213 configured as a pressure sensor is attached to the brewing chamber 12 that measures the instantaneous water pressure of the brewed water within the brewing chamber 12 during a brewing operation. The measurement signal 223 recorded in this way is directed to the control unit 210 configured as a regulator, which control unit 210 is in turn provided with a default signal 222 by means of the set point setting unit 212. The setpoint setting unit 212 may specify a regulating variable, such as the pressure to be maintained or the movement position of the valve piston 201 corresponding to the pressure to be maintained, which converts the control unit 210 configured as a regulator into a control signal 220. This control signal 220 is then fed back to the final control element 211, wherein the final control element 211 is typically configured as a motor, preferably a stepper motor.

As can be seen from the block circuit diagram of fig. 2, the control unit 210, the final control element 211, the setpoint setting unit 212 and the sensor 213 are connected to one another to form a control loop which can be implemented in a simple manner. Alternatively, only a control operation may of course be provided, instead of an adjustment operation. In this case, it is appropriate to avoid the use of the sensor 213 as shown in fig. 2. In this case, for example, if the final control element 211 is implemented as a stepper motor, the setpoint specified by the setpoint setting unit 212 may for example comprise a certain number of steps performed by the stepper motor.

Fig. 3 shows a cross-sectional view of the infusion unit 11, wherein it can be seen that the crema unit 21 and the final control element 211 configured as a stepper motor are completely housed inside the infusion piston 13. In this case, the final control element 211 is fixed inside the infusion unit 11 by fastening means 215, ensuring a reliable lifting and lowering of the valve piston 201. As also shown in fig. 3, the coffee sieve 14 is formed on a coffee passage 214, to which a counter pressure can be applied by means of the valve piston 201 and the stopper 202. The coffee screen is configured to retain the compressed coffee grounds 40 within the brewing chamber 12 and to allow only the liquid component (i.e., the brewed coffee) to pass in the direction of the coffee pathway 214.

In fig. 3, the valve piston 201 is shown in a condition in which the stop 202 is arranged at a distance D from the coffee passage 214 (movement position S1 of the valve piston 201) so that the coffee passage 214 is not closed by the valve piston 201, thus exposing a passage for the coffee brewed in the brewing chamber 12. However, if the valve piston 201 is moved to the movement position S0 shown in fig. 3, the stopper 202 closes the coffee passage 214.

As shown in fig. 3, the valve piston 201 includes a central longitudinal bore 201-1 and contains: at least one connecting channel 201-2, which realizes a fluid connection between the crema chamber 200 and the central longitudinal hole 201-1; and a connector 201-3 having one end of the outlet tube 30 attached thereto, wherein the connector 201-3 comprises a hole 201-4 enabling a fluid connection between the central longitudinal hole 201-1 and the outlet tube 30.

The pressurized brewing water initially flows in the direction of the sieve 14, wherein the direction of flow of the pressurized brewing water is indicated by the arrow marked with reference sign 41. During the brewing operation, the brewed coffee or brewing water passes through the coffee screen 14 and the coffee passage 214 into the crema chamber 200 while swirling with different intensities through the counter pressure from the stopper 202, depending on the path of movement of the valve piston 201 and on demand. The coffee beverage entering (through the connecting channel 201-2 and the holes 201-1 and 201-4) the outlet duct 30 configured as a tube therefore comprises crema of more or less intensity and of variable strength (depending on the displacement position assumed by the valve piston 201 during the brewing operation).

As further revealed by the sectional view of fig. 4, the brewing unit 11 is mounted in a rotary unit which allows automatic filling of the brewing chamber 12 with coffee powder before the brewing operation and subsequent emptying of the brewing chamber 12 after completion of the brewing operation (including removal of the coffee powder and, if desired and if present, removal of residues of the brewed water from the brewing chamber 12) by rotating the brewing cylinder 15 and by moving the brewing piston 13 (in the longitudinal direction of the brewing piston 13) and by moving the ejection piston 16 (in the longitudinal direction of the ejection piston 16). This rotation also causes the outlet tube 30 to rotate relative to the coffee outlet 31, which is not shown in fig. 4. The above-mentioned automatic filling and emptying of the infusion chamber 12 is known, for example, from EP0559620B1 and will therefore not be explained in detail here. With the solution according to the invention, it is therefore possible to position the piston 201 after the brewing operation, so that the residual liquid remaining flows from the outlet duct 30 back to the brewing chamber 12 through the coffee passage 214 and from there into a drip tray or similar water collecting device. This has the effect of preventing any residual water in the outlet duct 30 from being ejected out of the outlet aperture 31 during rotation of the brewing cylinder 15 (e.g., during automatic filling or emptying of the brewing chamber 12).

As further disclosed in fig. 4, a sensor 213 configured as a pressure sensor is provided for measuring the brewing water pressure acting on the brewing piston 13 during a brewing operation. This pressure sensor 213 is connected to a control unit 210, not shown in fig. 4, which is in turn configured as a regulator and issues a control signal 220, also not shown in fig. 4, to a final control element 211, i.e. a stepper motor in fig. 4.

Fig. 5 finally represents a schematic view of a brewing device 10 according to the invention, similar to that of fig. 1, wherein in this case the sensor 213 is configured not as a pressure sensor, but as a position sensor. Fig. 5 shows that the position sensor is integrated with the housing of the final control element 211. The position sensor may thus determine, for example, the movement position or the insertion depth of the valve piston 201 and issue a measurement signal 223 to the control unit 210 configured as a regulator. In fig. 5, the valve piston 201 is shown schematically displaced or moved to a position where no or less crema is produced than described in fig. 1.

Fig. 6 shows an assembly 21A comprising a crema unit 21 and a final control element 211, wherein the crema unit 21 or the final control element 211 corresponds to the brewing device shown in fig. 1 to 5 with respect to the configuration and function of the crema unit 21 or the final control element 211. In fig. 1 to 6, identical or similar functional parts are marked with identical reference signs. The arrangement of crema units 21 and final control elements 211 in the assembly 21A of fig. 6 differs from the arrangement of crema units 21 and final control elements 211 shown in fig. 3 and 4, since the assembly 21A can be positioned independently of the infusion unit 11, wherein the respective distance to the infusion chamber 12 can be chosen at will. In a configuration deviating from the brewing unit 1 shown in fig. 1 to 5, the crema unit 21 and the final control element 211 can be arranged outside the brewing piston 13 of the brewing unit 10. In this example, the assembly 21A comprises a housing 21-1 in which the crema unit 21 and the final control element 211 are arranged. In this variant, the assembly 21A forms a unit which as a whole can be positioned at a predetermined position.

As shown in fig. 6, the assembly 21A includes a connector 214-1, wherein the connector 214-1 is disposed outside the housing and is formed with a coffee passage 214 (corresponding to the coffee passage 214 of fig. 1 and 3-5) leading to the crema chamber 200. One end of the tube 12-2 may be connected to the connector 214-1 and the other end (not shown in fig. 6) may be connected to the brewing unit 11 to establish a connection between the brewing chamber 12 and the crema chamber 200 so that the coffee brewed in the brewing chamber 200 can flow into the coffee passage 214 via the tube 12-2.

For example, the assembly 21A of fig. 6 may replace the crema unit 21 and the final control element 211 of the infusion unit 11 shown in fig. 3 and 4, wherein only the coffee passage 214 of the assembly 21A must be connected to the outlet orifice 12-1 of the infusion chamber 12 via the tube 12-2. Instead of the tube 12-2, another suitable tube (e.g., a pipe) may of course be used.

In fig. 6, the valve piston 201 is depicted in a situation in which the stopper 202 is arranged in the movement position S0, thereby closing the coffee passage 214. The valve piston 201 is movable in its longitudinal direction by means of the final control element, for example to a movement position S1 shown in fig. 6, in which the stop 202 does not close the coffee passage 214, so that a fluid connection is established between the coffee passage 214 and the bore 201-4 via the crema chamber 200, between the connecting channel 201-2 and the central longitudinal bore 201-1.

As also shown in FIG. 6, assembly 12A includes a connector 30-1 having a longitudinal through bore disposed on housing 21-1 and serving to establish a fluid connection between bore 201-4 and outlet tube 30 for a particular prepared coffee beverage. As shown in fig. 6, the connector 30-1 comprises two ends provided for this purpose, wherein one end is connectable to one end of the outlet tube 30 and the other end of the connector 30-1 is connected via a tube 30-2 to a connector 201-3 of a valve piston 201, such that a specifically prepared coffee beverage can flow from the crema chamber 200 via the tube 30-2 into the outlet tube 30.

Claims (13)

1. An infusion device (10) for making a coffee beverage, wherein the infusion device (10) comprises:

a brewing unit (11) having a brewing chamber (12) for brewing coffee with brewing water that can be introduced under pressure into said brewing chamber (12);

a crema unit (21) for producing crema, having a crema chamber (200) connected to the brewing chamber (12) via a coffee passage (214) and having a valve piston (201) movable within the crema chamber (200) with respect to the coffee passage (214) to open and/or close the coffee passage (214); and

an outlet opening (31) for the outflow of a specific coffee beverage,

wherein the crema chamber (200) of the crema unit (21) is connected to the outlet opening (31) by an outlet tube (30) such that, for making a particular coffee beverage, coffee brewed in the brewing unit (11) during a brewing operation can flow through the coffee passage (214) and the crema chamber and reach the outlet opening (31),

wherein the valve piston (201) is movable such that a movement position of the valve piston (201) can be changed relative to the coffee passage (214), and the valve piston (201) can be brought into a plurality of different designated movement positions (S0, S1) such that the valve piston (201) tightly closes the coffee passage (214) when in one of the designated movement positions (S0) and is at a distance (D) from the coffee passage (214) and does not close the coffee passage (214) when in another designated movement position (S1),

wherein different successive brewing operations for making different coffee beverages can be realized in such a way that the valve piston (201) exhibits one of the specified movement positions in one of the brewing operations and another specified movement position in another of the brewing operations, and wherein the crema unit (21) is configured in such a way that the coffee brewed during the respective brewing operation swirls through with different intensities according to the respective specified movement position (S0, S1) of the valve piston (201),

it is characterized in that the preparation method is characterized in that,

a final control element (211) configured to vary the movement position of the valve piston (201) as a function of a control signal (220);

a pressure sensor (213) for providing a pressure reading of the instantaneous pressure of the brewing water in the brewing chamber (12);

a control unit (210) configured to generate the control signal (220) and to provide the control signal to the final control element (211),

wherein the control unit (210) is implemented as a regulator configured to receive the pressure reading provided by the pressure sensor (213) and to regulate, during a brewing operation, the movement position of the valve piston (201) according to a pressure set point for the pressure of the brewing water in the brewing chamber (12) such that the pressure of the brewing water in the brewing chamber (12) assumes the pressure set point.

2. The brewing device (10) according to claim 1, wherein the brewing device (10) comprises a set point setting unit (212) configured to generate the pressure set point and provide the pressure set point as a default signal (222) to the regulator.

3. The brewing device (10) according to claim 2, wherein the pressure set point is specified by a stored profile associated with a predetermined characteristic of crema.

4. A brewing device (10) as claimed in one of the claims 1 to 3, wherein the pressure set point is a static pressure set point over time or a variable pressure set point over time.

5. The brewing device (10) according to one of claims 1 to 3, wherein the crema unit (21) and the final control element (211) are arranged in a brewing piston (13).

6. The brewing device (10) according to one of claims 1 to 3, wherein the crema unit (21) together with the final control element (211) form a separate assembly (21A) which is spatially separated from the brewing unit (11), wherein the outlet opening (12-1) of the brewing chamber (12) is connected to the coffee passage (214) of the crema unit (21) via a duct (12-2).

7. The brewing device (10) according to one of claims 1 to 3, wherein the final control element (211) is configured as an electromechanical drive mechanism.

8. A method of making a coffee beverage with a brewing device (10), wherein the brewing device (10) comprises:

a brewing unit (11) having a brewing chamber (12) for brewing coffee with brewing water that can be introduced under pressure into said brewing chamber (12);

a crema unit (21) for making crema, having a crema chamber (200) connected to the infusion chamber (12) via a coffee passage (214) and having a valve piston (201) movable with respect to the coffee passage (214) to open and/or close the coffee passage (214); and

an outlet opening (31) for the outflow of a specific coffee beverage,

wherein the crema chamber (200) of the crema unit (21) is connected with the outlet opening (31) by an outlet tube (30) such that, for making a specific coffee beverage, coffee brewed in the brewing unit (11) during a brewing operation can flow through the coffee passage (214) and the crema chamber (200) and reach the outlet opening (31), wherein the valve piston (201) can be moved such that the position of movement of the valve piston (201) can be changed with respect to the coffee passage (214) and the valve piston (201) can be brought into a plurality of different specified positions (S0, S1) such that the valve piston (201) tightly closes the coffee passage (214) when in one of the specified positions of movement (S0) and at a distance (D) from the coffee passage (214) and does not close the coffee passage (214) when in the other specified position of movement (S1), wherein the crema unit (21) is configured such that coffee brewed during a respective brewing operation swirls through within the crema chamber (200) with different intensities according to respective assigned movement positions (S0, S1) of the valve piston (201),

wherein the brewing device (10) further comprises:

a final control element (211) configured to vary the movement position of the valve piston (201) as a function of a control signal (220);

a pressure sensor (213) for providing a pressure reading of the instantaneous pressure of the brewing water in the brewing chamber (12);

a control unit (210) configured to generate the control signal (220) and to provide the control signal to the final control element (211),

wherein the control unit (210) is implemented as a regulator configured to receive the pressure reading provided by the pressure sensor (213) and to regulate, during a brewing operation, the movement position of the valve piston (201) according to a pressure set point for the pressure of the brewing water in the brewing chamber (12) such that the pressure of the brewing water in the brewing chamber (12) assumes the pressure set point,

wherein for making a first coffee beverage during implementation of a first brewing operation coffee is brewed in the brewing chamber and during implementation of the first brewing operation the pressure sensor provides a first pressure reading for the instantaneous pressure of the brewed water in the brewing chamber (12) and the control unit (210) adjusts the position of movement of the valve piston (201) in dependence of the first pressure reading,

wherein for making a second coffee beverage during the implementation of a second brewing operation subsequent to the first brewing operation, coffee is brewed in the brewing chamber, and during the implementation of the second brewing operation, the pressure sensor provides a second pressure reading for the instantaneous pressure of the brewed water in the brewing chamber (12), and the control unit (210) adjusts the position of movement of the valve piston (201) in accordance with the second pressure reading.

9. A method according to claim 8, wherein the brewing device (10) further comprises a set point setting unit (212) which generates the pressure set point and provides the pressure set point to the regulator as a default signal (222), wherein the pressure set point generated by the set point setting unit (212) is specified by a stored profile which is associated with a predetermined characteristic of the crema.

10. Method according to one of claims 8 to 9, wherein, after the generation of a particular coffee beverage and the output of the coffee beverage through the outlet hole (31), the movement position (S1) of the valve piston (201) is set such that any liquid remaining in the outlet duct (30) that is not output from the outlet hole (31) flows back to the brewing chamber (12).

11. Method according to claim 10, wherein the infusion device (10) further comprises a coffee sieve (14) arranged between the crema unit and the infusion chamber (12) at the coffee passage (214), and wherein the residual liquid flows back from the outlet duct (30) through the coffee sieve (14).

12. Method according to claim 10, wherein the liquid that has flowed back into the brewing chamber (12) is emptied into a residual water container.

13. Method according to claim 11, wherein the liquid that has flowed back into the brewing chamber (12) is emptied into a residual water container.