DE4409030C2 - Process for the production of coffee beverages and a suitable coffee machine - Google Patents

Description

The invention relates to a method for automatic Preparing a coffee drink in the preamble of claim 1 explained type and on a suitable coffee machine Claim 9.

Such a method is known from US 4,621,571 A. The coffee machine used for the known method has a hot water tank on a hot water pipe is connected to a spray head, which is above a brewing is arranged. The brewing unit is made as a filter holder formed and absorbs filter paper and ground coffee. Of the Hot water pipe branches between the hot water tank and another line from the spray head, which is regulated by a regulable res bypass valve can be shut off. The other line leads also into the brewing unit, but bypasses the filter paper with the ground coffee, so that from the further line if hot water escapes bypassing the ground coffee flows through the brewing unit directly into a storage container, into which the coffee stock from the ground coffee also gets.

With this possibility, hot water bypassing the coffee to be able to feed flour directly into a storage container an over-extraction of the ground coffee and thus a bitter coffee be avoided. It was also found that an over-extraction with soft water with one for extraction the smaller amount of hot water used can occur, than is the case with hard water. The bypass valve was thus designed to be adjustable in order to bypass the amount of hot water to be able to adjust according to the water hardness. The bypass valve however remains open throughout the brewing cycle, so that Hot water from the beginning to the end of the brewing cycle in the pre  advice container arrives. There is thus in the storage container only at the end of the brewing cycle a coffee drink in drinking strength.

From DE 27 14 736 A1 or DE 41 30 446 A1 it is also known for manually operated household machines, a Part of the hot water used to prepare the coffee bypassing the ground coffee directly into the jug However, this also only serves to limit the contact time of the Reduce beverage raw material with hot water, so less unwanted bitter substances are leached out. DE 27 14 736 A1 shows this a tea machine that also has hot water in the jug flows after first over a predetermined con cycle time hot water has run through the tea leaves. DE 41 30 446 A1 shows a household coffee machine in which Brewing large amounts of hot water bypassing of the ground coffee is fed directly into the jug. If the However, the introduction of hot water has been started once is, it remains for the entire duration of the preparation constant until the end. With both machines is also only obtained at the end of the preparation cycle a drink of drinking strength.

In contrast to the present invention, the task reasons, a method and a coffee machine for the production of coffee beverage to deliver, where already during a filling process Can be tapped.

The task is characterized by the characteristics of the contractor spell 1 solved.

The regulated admixture of hot water at the beginning of the Preparation cycle while the concentration of the drink If the drink is still above drinking strength, the prepared coffee will be immediately diluted to drinking strength, so that without blocking period at the beginning of the Preparation cycle can be tapped from the reservoir.  

Advantageous developments of the invention are the Un claims.

Claim 2 describes a particularly preferred tax tion of the supply of additional hot water, because with it unavoidable fluctuations in raw material quality or Like. Can be compensated without the danger be stands that the coffee drink is too thin.

In claims 3 and 4 are particularly preferred Procedures for adding hot water described.

Claims 5 and 6 describe modes of operation which particularly in the production of filter coffee have proven.

By the measure according to claim 7, the mixture degree of both subsets improved, which is particularly true with a discontinuous, clocked addition of the hot water has a positive effect.

Claim 9 describes a particularly preferred embodiment Rungsbeispiel one for performing the invention suitable coffee machine.

By the embodiment according to claim 10, the Vermi improved the two subsets.

The level measurement specified in claim 11 can thus probably for corresponding level indicators for manual Initiate a post-brewing process, or for those in To according to saying 12 automatic refill or, according to Claims 8, 13 used for the tap  monitor the progress of the preparation cycle and dispensing a residual amount of coffee from the storage container lock at the beginning of the preparation cycle, d. H. too much coffee already during the hot water supply was tapped so that there could be a risk that the concentration of the remaining coffee is too far falls below drinking strength.

An embodiment of the invention is as follows explained in more detail with reference to the drawings. Show it:

Fig. 1 is a schematic representation of a coffee machine with the most important parts for the present inven tion, and

Fig. 2 is a diagram of the concentration curve over the brewing amount under different conditions.

A coffee maker 1 shown schematically in Fig. 1 has a summarized by a boundary shown as a housing 2 of a unit with a heater 3 provided a hot water heater 3 and a brewing unit. 4 A control device 5 is also accommodated in the housing 2 . The hot water heater 3 , the brewing unit 4 and the control device 5 are of a conventional type. The brewing unit 4 is assigned a portioner 6 for coffee flour. The scoop 6 contains the übli che dosing screw for dosing the required amount of ground coffee and is either itself designed as a storage container or connected to such, which can also be placed on the outside of the housing 2 in a manner not shown. Instead of ground coffee, however, coffee beans can also be stored in a known manner, the portioner 6 or the storage container additionally being assigned a coffee grinder.

The hot water heater 3 can be filled via a water line 7 leading into the housing 2 from the outside. The water heater 3 and the brewing unit 4 are connected to each other via a brewing line 8 , which can be shut off by a brewing valve 8 a and in which a flow meter 8 b is arranged. From the brewing unit 4 , a waste water line 9 leads out of the housing 2 , through which the used coffee is rinsed out. With the brewing unit 4 , a coffee outlet line 10 is also connected, which opens into a reservoir 11 before.

The reservoir 11 is isolated and / or provided with a self-heater 12 and has a spout 13 into which an operated by the controller 5 Zapf valve 13 a arranged to be filled on the portion such as cups or pots.

With the hot water heater 3 , a further hot water line 14 is connected, which can be shut off by a valve 14 a arranged inside the housing 2 and in which a flow meter 14 b is also arranged. The hot water line 13 connects the brewing line 8 upstream of the valve 8 a with the coffee outlet line 10 between the brewing unit 4 and the storage container 11 . Through the hot water line 14 in the manner described below, the coffee outlet line 10 , and thus the drink in the storage container 11 before mixed with hot water. If necessary, a further line can be connected to the hot water heater 3 for the direct delivery of hot water into portion vessels (not shown).

The reservoir 11 contains an automatic level measurement 15 , z. B. in the form of spaced one above the other level electrodes 15 a, 15 b, 15 c, with which it can at least be determined whether the reservoir 11 is completely filled or completely empty. With this level measurement 15, however, the current status or the level in the reservoir 11 can preferably also be determined.

These level electrodes 15 a, 15 b, 15 c are each connected to the control device 5 via signal lines. As also indicated by lines, and the dispensing valve 13 a, the valve 14 a, the brewing valve 8 a and 8 b are Durchflußmengenzähler and 14 b connected to the control device. 5 In a known manner, the heater 3 a of the Heißwas serferters 3 , the brewing unit 4 and the scoop 6 are connected to the control device. The control device 5 is acted upon by manually operated dials, not shown, on the outside of the housing 2 . Example intended as a first brewed coffee load and be introduced into the ago storage container 11, so the entspre sponding dial is operated and metered into the (pre-purified) brewing unit 4 by the scoop 6, the appropriate amount of ground coffee. Then the brewing valve 8 a is opened and hot water flows into the brewing unit 4 . Depending on the type of brewing unit 4 , the brewing process is repeated or closed by closing the brewing valve 8 a until the predetermined amount has been brewed, ie, the predetermined amount of hot water from the hot water heater 3 for the predetermined amount of ground coffee in the brewing unit 4 was removed.

The control device 5 is provided with an automatic refill device which automatically initiates the required brewing process or processes in order to refill the storage container 11 in good time. The automatic refill contains a memory for storing various operating specifications. So it is possible, for example, when using the coffee machine in hospitals or at days or the like. Where the approximate point in time of an increased need for coffee beverages is foreseeable, these times can be saved in such a way that the automatic refill, controlled by a timer, ensures this that the storage container 11 is filled at this time. In addition, the fill level measurement solution 15 in the reservoir 11 is connected to the automatic refill, so that if the minimum fill level is undershot, the who can be brewed if necessary. In order to determine whether it is necessary to brew at all, a need to be estimated, for example when using the coffee machine in hospitals or the like, can be saved, and the storage container 11 can only be refilled until the amount of coffee corresponding to the estimated need appropriate coffee was filled in the reservoir 11 .

Each brewing process in the brewing unit 4 initially delivers a drink that is too strong to drink and is only diluted to drinking strength by the continuously weakening drink at the end of the brewing process. In order to create a possibility of being able to constantly tap from the reservoir 11 , as explained below with reference to FIG. 2, the hot water line 14 and the valve 14 a of the coffee outlet line 10 or the reservoir 11 are mixed with hot water directly. The admixture he follows cyclically or continuously but quantity-controlled, over a more or less strong opening and closing of the valve 14 a in a predetermined manner, so that the Ge drink in the reservoir 11 always has about drinking strength and can be tapped at any time.

Fig. 2 shows a simplified graphic representation of the trend of the beverage concentration over the brewing amount in different operating states. For the purposes of the present illustration, the total amount of brewing, which is adapted to the capacity of the storage container 11 and is approximately 5 liters, was divided into twenty equal portions of approximately 0.25 liters. Only the quantitative sequence of the passage of the individual subsets from 1 to 20 was shown, whereby the brewing time was not taken into account. The curves were shown as lines, although in practice, depending on the quality of the raw material used, the brewing speed, the degree of grinding and the special brewing system, there is a lot of scattering, but this was not taken into account for reasons of clarity.

Curve I shows the trend of the concentration of the coffee beverage that runs directly out of the brewing unit 4 . Curve II shows the tendency of the concentration in a storage container of the prior art when the beverage escaping from the brewer is introduced into the storage container without water admixture and is accumulated there. Curve III shows the tendency of the concentration of the beverage in the reservoir 11 when hot water is mixed in according to the present invention. The horizontal line IV denotes the drinking strength, ie the concentration with which the coffee drink is ready for consumption and can be poured into drinking vessels. This drinking strength is different depending on the type of drink and depending on the drinking habits of the consumer and is, for example, 1.3 to 1.9% for cream coffee or 0.8 to 1.5% for filter coffee, ie the drinking strength is over a certain concentration range the breadth of which depends on consumer habits and consumer acceptance, and is shown as a line only for reasons of clarity.

The drinking strength is the final concentration of the Kaf fairy drink by measuring the relations between Amount of ground coffee and used Brewing water is sought.

As curve I shows, the concentration of the coffee escaping from the brewing unit 4 initially rises within the first subset by swelling the ground coffee from point A to point B, the concentration at point B being a multiple of the drinking strength the brewing unit 4 leaking coffee is too strong to drink. Subsequently, however, the concentration of the coffee escaping from the brewing unit 4 drops relatively sharply until after the passage of the fourth partial amount in point D it drops below drinking strength. Then the concentration curve of the coffee escaping from the brewer approaches asymptotically to zero, whereby the coffee that last escapes is almost colorless. If, as is practiced in the prior art, one would pass all twenty subsets through the brewing unit and then collect them in a storage container, the concentration curve in this storage container would correspond approximately to curve II. In the storage container there would first be a very strong coffee, the vertex G of curve II being approximately half the distance A - B of curve I due to the dilution effect of the coffee with lower concentration that initially entered the storage container. Then the concentration in the storage container also drops, but flatter than curve I, so that the drinking strength on line IV is reached at point H when the storage container is filled with all twenty subsets. The trend of curve I clearly shows that drinking strength coffee can only be tapped if all twenty brewing quantities have been accumulated in the storage container, so that the coffee, which was initially very strong, was diluted by the quantity below strength at the end of the brewing process.

According to the present invention, a concentration curve during the brewing cycle is aimed at in the storage container, which in the ideal case is identical to line IV, ie the concentration of the coffee beverage in the storage container should always be on drinking strength, no matter how many of the portions of a brewing cycle are already in the storage container are located. In practice, this ideal curve can only be achieved with a disproportionate amount of measurement and control effort due to a certain spread of the concentration values. The actual concentration course of the coffee beverage in the storage container during each brewing cycle will therefore represent a compromise between an acceptable level of measurement and control effort and the concentration achieved, the concentration course in the storage container always being within the acceptable range of drinking strength or oscillating around line IV , as shown by curve III in FIG. 2. For an ideal course of the concentration curve in the reservoir 11 , each would have to be exactly on the concentration of the escaping from the brewing unit 4 (curve I), provided that this concentration is still above drinking strength (points A - B - C - D), respectively a tuned to the current concentration of the partial amount currently running through the brewing unit 4 amount of hot water is supplied, while the flow through the brewing unit 4 and the supply of hot water must be stopped as soon as the beverage unit 4 has a drinking strength (point D ).

However, in order to take into account the large variations in operation, the hot water supply is stopped when the coffee running out of the brewing unit 4 has the concentration in point C, ie is still above drinking strength. It was also found that a good approximation to the ideal line IV is achieved when half of the brewing amounts, ie ten portions, hot water is fed directly to the storage container 11 and the other half, ie again ten portions, of the coffee beverage from the Brewing unit 4 comes. All ten portions of the hot water must of course have been fed to the storage container 11 before the coffee emerging from the brewing unit 4 drops under drinking strength. As shown in FIG. 2, at a concentration at point C, about a third, ie three portions, of the coffee has passed through the brewing unit, with ten portions of hot water directly into the reservoir 11 at this time, not evident in FIG. 2 were directed. This results in the course of curve III between points K and L for the first thirteen subsets in the storage container. The water supply is clocked or gushing, so that the slight undulations of curve III result between points K and L, or continuously , but different in the amount, where the surge amount or the amount of continuous supply is matched to the changing concentration of the coffee passing through the brewing unit 4 . Since the mixing of hot water and coffee from the brewing unit takes place before both reach the reservoir 11 , however, the concentration in the reservoir is relatively balanced.

After the hot water supply stops after ten portions, coffee continues to run from the brewing unit 4 into the storage container 11 until all ten portions have passed through the brewing unit 4 . Since the concentration between the third and fourth subsets (points C - D) is still above drinking strength, curve III rises slightly between points L and M after the hot water supply has ended. Then the concentration of the coffee from the brewing unit 4 drops between the points D and E, so that the coffee in the storage container 11 is further diluted with a tea drink until its concentration has dropped to the point N. It can be ensured by a somewhat increased amount of ground coffee that the end point N of curve III is not too far below the ideal line IV.

From the above explanations it follows that the concentration curve of curve III does not change or does not change significantly, at least until the thirteenth subset has entered the storage container 11 , ie until the end of the hot water supply, regardless of whether and how much coffee is tapped from the storage container 11 becomes. However, the curve of curve III between points L and N can change if too much coffee has been tapped beforehand. About the level measurement 15 in the storage container can be ensured that when the fill level in the storage container is too low after the hot water supply the tapping of a residual amount of drink remains locked until the next brewing cycle. For this purpose, the control device 5 contains a lock, which prevents opening of the nozzle 13 a, but the lock can be released if the reservoir 11 is to be completely emptied.

The admixture of hot water was explained in FIG. 2 on the basis of the concentration curve when brewing coffee, but it can be modified in an analogous manner for the production of other types of beverages, such as tea from tea leaves.

As a modification of the described and drawn version For example, the nozzle can also be operated manually tes valve be formed. The function of the flow The quantity counter can also be controlled by a time control ordered valves are taken, the brewing valve and the hot water valve according to a predetermined pro Gram opened or closed over predetermined times will.

Claims (13)

1. A method for the automatic preparation of a predetermined amount of a coffee beverage from a predetermined amount of coffee grounds and a matched, predetermined amount of hot water, wherein only a subset of the predetermined amount of hot water for extracting the beverage is extracted for extraction through the coffee grounds and into one Storage container arrives and the remaining part of the hot water flows directly into the storage container, bypassing the ground coffee, characterized in that hot water is passed directly into the storage container bypassing the ground coffee and this hot water supply is ended before the coffee water supply is bypassed Concentration of the portion flowing through the ground coffee falls below the drinking strength, and that the respective partial amounts of the hot water are determined in such a way that the coffee has drinking strength in the reservoir during the hot water supply. 2. The method according to claim 1, characterized in that the The supply of the partial amount of hot water to the storage container has ended when the concentration of the coffee powder has flowed Nine subset is still above drinking strength. 3. The method according to claim 1 or 2, characterized in that the subset of hot water clocked to the reservoir leads. 4. The method according to claim 1 or 2, characterized in that the subset of hot water continuously the reservoir but regulated in terms of quantity, is fed.   5. The method according to any one of claims 1 to 3, characterized records that each subset about half of the predetermined Amount of coffee made in a brewing cycle drinking corresponds. 6. The method according to claim 5, characterized in that the total subset of hot water the reservoir during the Inlet of about the first third of the coffee ground flowed subset is supplied. 7. The method according to any one of claims 1 to 6, characterized records that the subsets before reaching the storage container be mixed. 8. The method according to any one of claims 1 to 7, characterized records that the level in the reservoir is determined and tapping is blocked after the hot water supply has ended is abge when the level below a predetermined value is sunken. 9. Coffee machine for performing the method according to any one of claims 1 to 8, with a control device for self-preparing coffee beverage, a hot water ter, a brewing unit, a reservoir connected to the brewing unit via a coffee outlet line and a beverage container for coffee Dispensing device for coffee drink, the hot water heater being connected directly to the storage container via a valve provided with a hot water line for admixing hot water to the coffee drink contained in the storage container, characterized by a valve ( 14 a) of the type-controlling device ( 5 ) that only at the beginning of the preparation cycle hot water bypassing the ground coffee di can be introduced directly into the storage container ( 11 ) and this hot water supply is terminated before the concentration of the portion flowing through the ground coffee falls below drinking strength, and that the respective portions of the H Iced water can be tuned in such a way that the coffee beverage in the storage container ( 11 ) has drinking strength during the hot water supply. 10. Coffee machine according to claim 9, characterized in that the hot water line ( 14 ) opens into the coffee outlet line ( 10 ) in front of the storage container ( 11 ). 11. Coffee machine according to claim 9 or 10, characterized in that the storage container ( 11 ) is provided with an automatic level measurement ( 15 ) which is connected to the control device ( 5 ) via a signal line. 12. Coffee machine according to claim 11, characterized in that the control device ( 5 ) has an automatic refill for automatically initiating a preparation cycle and filling the storage container ( 11 ) as a function of its fill level. 13. Coffee machine according to one of claims 9 to 12, characterized in that the control device ( 5 ) has a switchable dispensing valve ( 13 a), which prevents the dispensing of a residual amount of coffee from the storage container ( 11 ).