DE102005004416A1 - Drinks preparation procedure measures scattered light from illumination of drink and stops preparation when preset value reached - Google Patents

Abstract

A drinks preparation procedure measures scattered light (9) from illumination of the drink and stops (13) preparation when a preset value correlated with the required concentration (7) is reached. Independent claims are included for a drinks preparation machine using the procedure.

Description

The The invention relates to a method for preparing beverages, wherein the construction correlates with the translucency of the beverage, in particular for preparing coffee and a corresponding one Beverage maker, especially a coffee maker.

in the The following is generally spoken of coffee, but can also other drinks, such as tea, etc., to be prepared this way.

A good Coffee "with help about a filter coffee machine is due to a variety of unrecognized parameters and also by inadequacies in the preparation of the drink more or less a random product.

It There are a variety of methods for the preparation of drinks, in particular a coffee drink from roasted or ground coffee beans. Has prevailed, at least in the Area of cheaper home coffee makers the upcoming Brühprinzip where in a V-shaped Paper filter a dosed amount of ground coffee with hot water brewed becomes. In such coffee machines, the hot water is through an opening in passed the filter with the ground coffee. The inflowing amount of water is tuned so that only the amount is added, the through a small opening at the bottom of the filter into a container, For example, in a glass jug or in a thermos drains.

The Result is through the initial big water intake of the coffee powder and the relatively small drainage opening at the bottom of the filter a balance, so that the entire regrind surrounded with water is and so relatively evenly washed out can be.

Practice has shown that this method of preparation has some disadvantages:
Due to the occurring depending on the local water hardness at intervals calcification of the beverage maker increasingly overcooked much water, which is actually needed for the production of coffee. The result is too concentrated coffee.

The Coffee powder is usually with measuring spoons filled in the filter, being different in dosage, for example due to different heaped measuring spoons also result in different concentrations of the coffee.

The common Cause to not get the coffee in the desired concentration, is a wrong insertion of the required portion quantities in relation to the desired Coffee concentration, for example, a weak, medium or strong coffee.

As well have to depending on the planned amount of drinking different amounts of powder each Cup can be used, with low amounts of coffee through the Type of filter technology proportionally more coffee powder per cup used must be as with larger amounts of drink.

It has already been suggested, the concentration of coffee independently from the mentioned To design parameters.

For this gets into the drink Light irradiated, which is attenuated by the drink and the recipient directly received light is measured. The preparation process for the drink is interrupted when the measured value for the attenuated light a given drink reached.

According to the US patent 5,724,882 is one in the red or infrared Light emitting light source and a photodetector used, wherein the light source and the photodetector on the opposite Sides of a transparent container for the Coffee are arranged.

With acceptable light output, however, is a radiation of the entire container not possible. A strong coffee allows for directional light, for example the light of a laser diode, a fluoroscopy range of some Centimeters, for example, 4 centimeters, which is well below the Diameter of usual container cans for the Coffee falls below.

by virtue of This finding is suggested in US-A-3,560,714 which Reduce fluoroscopy. For this purpose, the coffee container, d. H. the coffee pot in the bottom area with a protruding nose-like Provided insert that has only a small thickness. Only this Insert is irradiated by the transmitter, which is through the coffee weakened Light on the opposite Side of the receiver Will be received.

This System needed however, a special construction of the coffee container or the coffee pot, adding that the nose-shaped approach is difficult to clean which also influences the measurement results obtained can.

In US-A-3 576 646 it is mentioned that lan ge Durchleuchtungsstrecken in coffee or other drinks are not possible because of the high absorption of light radiation. For this reason, according to the aforementioned US patent, a reflection mirror is installed in the coffee pot, whereby a required low transillumination path is made possible.

Also this solution is for the practice is not suitable, because the mirror in the pot a thorough cleaning hardly possible and if the mirror is soiled, the measurement results achieved become useless.

Of the Invention is based on the object, a method and an apparatus or a beverage maker to provide drinks, with those independent from external influences the Concentration of the beverage always reliable is reached.

These Task is in accordance with the invention by the characteristics of the independent claims solved.

Therefore will that be in the drink scattered light of the incident light is measured, with upon reaching a predetermined setpoint for the measured value the preparation of the beverage is interrupted. For this Both a transmitter and a receiver are adjacent located and arranged so that the recipient of the scattered by the drink Receives stray light, wherein upon reaching the setpoint a control module prepares of the beverage interrupts. At certain wavelengths may possibly also fluorescent light occur whose dispersion is also perceived.

transmitter and receiver can for example, with a transparent container for the beverage, for example a coffee pot, be integrated in the handle of the pot, for example on one Crossbars nearby the bottom of the pot. It is crucial that the functional elements the entire measuring device are arranged so that on the one hand a relatively short transillumination path arises and on the other hand this Positioning perfect access to the individual functional elements allows one for the optimal function required thorough cleaning of these components and to ensure functional areas.

In in each case, the functional elements are located outside the container for the beverage, so special designs for not these containers necessary.

It is also possible for the Measurement of laser radiation for measuring the light transmittance or the absorption of the beverage use. For this purpose, the light is radiated into the drink and leaves the drink after a short straight distance, in which case this attenuated light measured and upon reaching the predetermined target value, the preparation of the beverage is interrupted.

For the measuring method The principle of attenuated total reflection can also be used: Falling light through a medium having a relatively high refractive index, in this special case, for example, the glass bottom of a coffee pot, under a bigger than the critical angle of incidence for the total reflection on the interface to a medium with smaller Refractive index, in this case the refractive index of the beverage, so is the radiation in the optically more permeable material, that is in the Bottom of the glass container reflected back. Part of the radiation penetrates slightly into the optically opaque one Medium, that means that drink or the coffee, and is absorbed there. The intensity change The light radiation is measured, which allows conclusions about the concentration of the drink pulled who can. Once a predetermined setpoint for the attenuated light is reached, the preparation of the beverage is interrupted.

It is possible, the light reflected at the boundary layer several times in the direction to reflect back to the boundary layer, before the intensity of the multiply reflected and attenuated light is measured.

Further Embodiments of the invention will become apparent from the dependent claims.

The Invention is based on embodiments closer to the drawing explained. In this represent:

1 a conventional filter coffee machine with a transmitter and a receiver for measuring the concentration of coffee;

2 a schematic plan view of the transmitter and the receiver in the coffee machine according to 1 ;

3 again a schematic representation of the transmitter and receiver;

4 a schematic representation of another embodiment with a transmitter and receiver for a scattered light measurement according to the invention;

5 a schematic plan view of the transmitter and receiver according to the embodiment in 4 ;

6 a partial section through a coffee machine with a transmitter and a receiver for a transmitted light measurement according to the invention;

7 a schematic representation of the arrangement in 6 ;

8th a schematic representation of a coffee pot with a measuring system with attenuated total reflection;

9 a schematic representation of the arrangement in 8th with a multiply reflected light beam;

10 a schematic representation of a coffee machine with the measuring principle of the attenuated total reflection.

Of the Sequence of the measurement according to the invention the coffee concentration and the control of the addition of water during brewing process, should be present on behalf of all other coffee and tea making processes Hand of a commercial household electric coffee maker with paper filter.

The representations ( 1 ) of the hot water production and the brewing process represent only the current state of the art. The method according to the invention can be used in principle with all popular coffee machines or coffee machines.

The 1 shows the principle of the coffee machine in its entirety. The water reservoir 1 It should be designed so that it can be easily removed from the machine, so that in addition to the simple filling, even the unnecessary excess water can be easily disposed of again.

A comfortable alternative would be In this context, a direct connection of the machine to the Domestic water supply. Due to the always same quantities, there are relatively for this purpose simple installation solutions, especially if the coffee maker is near one Tap for the house water supply can be set up.

With the help of the illustrated arrangement heating resistor and check valve 2 This will be from the water reservoir 1 extracted water heated and over the pipeline 15 in the coffee filter 14 directed. This inflowing amount of water is adjusted so that they are affected by the rel. small opening at the bottom of the filter sufficiently drains, without the filter overflows. Due to the initially high water absorption of the coffee powder, an approximately constant degree of filling in the filter quickly sets in, through which the entire ground material is surrounded with water and thus can be washed out relatively evenly.

Initially, a very dark colored coffee extract flows into the can container 12 which then becomes slow but increasingly brighter.

The first light impermeable, but increasingly brighter coffee has sometime between the light diode 9 and the transistor 9b , For example, a CMOS transistor, a light transmittance reaches that of the previously set coffee concentration 7 , ie corresponds to a first setpoint. This reading will now be from the control module 5 detected, which via the switch 3 switches off the heating resistor. Alternatively, however, could the water inlet through a corresponding valve 13 be stopped directly. The management of the control pulses takes place in the example drawing analogous to the electrical power supply of the functional parts on the Kannenfuß 8th , There are also several alternatives for this.

So can e.g. both the power supply and the electrical control using direct contact plugs via spring contacts, how to it from the hot water cookers knows her, be accomplished.

Farther but would be also at a suitable location an inductive transmission of the electrical Energy and the measured values or control pulses conceivable.

If a manufacturing process is chosen in which the coffee filter is constantly kept at full level, the water supply must be switched off beforehand, as the filter contents are still running. Unless the feed is controlled from the filter directly through a closing valve below the filter 13 ,

The Capacities of the coffee powder and the associated amounts of water are like that set that enough Travel for estimation error remains. A normal coffee cup has a capacity of about 125 ml. If the coffee maker e.g. For 6 cups to be designed, will be a water reservoir of 1 liter proposed. With 6 cups of 125 ml, exactly 750 ml of water would be required. 250 ml excess allow it, even very rough estimation errors to correct.

A second measuring mark could be attached to the water reservoir with half a liter of water be that for max. 3 cups is assigned. Here, the excess water with 125 ml would be sufficient.

The Orientation to the maximum capacity of the coffee powder then becomes possible if the funnel-shaped Insert for receiving the filter bag a transparent plastic is made. Because the filled coffee flour through the paper filter can be seen using a marker line the maximum permissible capacity are displayed.

in the The measuring methods according to the invention are presented below:

Use of scattered light:

In the pitcher handle 11 is a version of the device according to the invention installed in the bottom area of the pot: It consists first of a light barrier, by a stray light source 9 as an emitter, eg a light diode, and a light-sensitive detector 9b is formed as a receiver (see in addition thereto 2 and 3 ). The electrical supply of the light diode and the detector is effected by the low-voltage transformer 4 about the contact 6 and the contact in the Kannenfuß 8th via which the control signals are also transmitted.

Alternatively to the electrical supply as well as the signal transfer of the functional parts, can however also with the help of light guides as in the 9 (Pos.29) is shown, the emitter are supplied directly with light, which was generated in the housing of the coffee machine. Via plug-in adapter 30 , both the light supply of the light barrier can be done, as well as the transmitted light (emitted light intensity - absorption amount) are returned and measured in the coffee machine or evaluated.

The Advantages of using optical fibers are in particular that with open accesses To electrical contacts the potential risks, as in the kitchen area in which water is handled, can be excluded.

The 4 and 5 show once again the same principle in a different positioning of the light barrier. In this arrangement, the functional elements in the foot of the coffee maker plug contacts and optical adaptations to the pot are superfluous. Emitter and detector housings receive conical outer contours for optimum alignment of the can 16 that recur in the bottom area of the can insulation.

The figures further show that the central area of the can bottom is curved slightly inwards, so that coffee residues, which would have dried up contaminate the measuring area, into the resulting gutter 17 can drain on the edge of the pot.

On a further arrangement possibility of the light barrier or the corresponding functional parts has the "X" ( 4 ) designated area opposite the can handle. Here too, the functional parts of the light barrier, as in the previous solution, remain in or on the housing of the coffee machine.

Use of laser light:

The use of laser light allows a precise detection of the light transmission of the measuring medium. A commercially available, extremely inexpensive laser diode 20 , as you know, for example, from the laser pointer, is installed as a light source (see 6 and 7 ). A glass body 18 with a reflective surface 23 serves at a suitable location on the pitch surface for deflecting the light beam to the light detector 19 ,

By a relatively close arrangement of the functional parts to each other, can the required small measuring distance can be realized.

Instead of the reflection mirror, it is also conceivable, at this point the light detector 24 directly insert, whereby the fluoroscopy section is still halved.

Also here there is the possibility the light diode and possibly the receiving transistor with respect to the can handle in the case to lay the coffee machine.

So that the glass body with its mirror surface or the light detector can be placed on the can surface of the coffee maker, it is necessary to use the middle can bottom 22 to move into the pitcher room. The laser beam or alternatively a focused light inevitably becomes the bottom glass 21 to illuminate the pot, whereby a change in direction of the light beam takes place, which must be taken into account accordingly.

Attenuated total reflection (ATR):

The 8th . 9 and 10 show the use of a measuring method in which the light absorption can be measured from the outside.

If light falls through a medium with a relatively high refractive index (here the glass bottom of the pot 25 ) at a larger than the critical angle of incidence on the interface to a medium with a smaller refractive index (here the coffee beverage), the radiation is in the optically more permeable Material (glass jug bottom) reflected back. Part of the radiation penetrates slightly into the optically more opaque medium (coffee) and is absorbed there. The change in intensity of the light radiation is measured, allowing conclusions about the coffee concentration can be drawn.

In the 9 becomes the light 27 several times at a predetermined angle from the mirror 28 or the interface Kannenboden / coffee reflected. The sum of the reflection losses, allows a very accurate statement about the concentration of the coffee.

As an exemplary embodiment, the light coupling and decoupling by optical fibers 29 via so-called SMA plug (stright medium adapter) 30 respectively.

A very simplified version of this principle is in the 10 shown. Here, both the laser diode and the light transistor are at a suitable angle below the can bottom in the coffee machine housing 32 Installed. In this design, the light is subject to a further refractive index, so that attenuated total reflections take place in the boundary regions of the media air / glass / coffee.

Through a window 31 In the thermal can insulation an optical access to the measuring medium is created. It can be assumed that the absorption amount is sufficient to achieve a satisfactory determination of the coffee concentration.

All Methods and methods, whether they work with "scattered light", "laser light" or the "attenuated total reflection", are in principle for the intended purpose sufficiently precise; especially if at the beginning of each brewing process Calibrating zero adjustment of the respective system takes place. If the coffee maker is now calcified or too much or too little coffee powder filled in the filter was the previously set coffee concentration (weak, medium, strong) is produced consistently in each case.

As it always works with a surplus of water, for example, a too strong coffee can also be done retrospectively by simply adjusting the adjusting knob 7 be diluted accordingly.

Basically it is possible in all procedures to use the coffee pot as an open glass container, or even as a light impermeable To use insulating jug. With the help of intelligent electronic Control circuits can be both the external light influence and the degree of pollution be automatically compensated.

In order to no health risks arise from the measuring light, and that applies to all measuring principles, an appropriate circuit should ensure that only the measuring device works, if the light radiation can not do any harm.

Vending machines and food court:

According to the invention can also measure concentration in the vending and catering sector according to one or more of these measuring principles directly in a portioning device or but at another suitable location e.g. immediately before Tapping point carried out become. to control the coffee or water supply accordingly. The previously set coffee concentration (low-medium-strong) would be like that can be made individually in a relatively simple way, which also for commercial Vending machine is interesting.

The Possibility. according to these principles drinks Of course, setting up with consistently consistent quality is not limited to coffee only. Basically it for all drinks suitable, their light transmittances to change in the manufacturing process.

The advantages of the invention over the prior art are among others:
The coffee concentration (low-medium-strong) can be adjusted individually.
The set coffee concentration, regardless of the amount of coffee flour and the degree of calcification of the coffee maker, always the same.
If, for example, too little ground coffee for the set coffee concentration and the planned production quantity were filled into the machine, the amount of drinking will be correspondingly smaller. The set concentration is maintained in every case.
This increase in comfort is made possible by continuous measurement of the light transmission of the coffee beverage and a fundamental excess of water in the production process.

Important In this context is that without much technical effort the Coffee strength very much can be set exactly and reproduced consistently.

• 1. Da bei herkömmlichen Kaffeemaschinen die Wärmezufuhr durch die Warmhalteplatte unabhängig von der warm zu haltenden Kaffeemenge immer gleich ist, wird zur Schonung des Kaffeearomas vorgeschlagen, neben der individuellen Einstellbarkeit die Warmhaltetemperatur der jeweiligen Kaffeemenge anzupassen.
• 2. Weiterhin kann z.B. durch ein im Kannengriff installiertes Display sowohl die Kaffeetemperatur als auch die Kaffeemenge, wie viele Tassen in einer Thermoskanne noch zur Verfügung stehen, kontinuierlich, in Zeitabständen oder abrufbar angezeigt würden.
• 3. Beim Einsatz eines Kondensators oder elektrischen Akkumulators und/oder mit Hilfe des Peltiereffektes kann die elektrische Energie für die Anzeige der Kaffeetemperatur und Kaffeemenge ohne umständlichen Batterieaustausch dauerhaft sichergestellt werden.
• 4. Wenn das Kaffeegetränk lange vorgehalten werden muss, ist es bei der Isolierkanne sinnvoll, den Kannenboden wärmedurchlässig zu machen und den Wärmeverlust durch eine sehr geringe Wärmezufuhr zu kompensieren.
• 5. Weil in der Küche häufig Flüssigkeitsmengen gemessen werden, kann das abnehmbare Wasserreservoire diese Aufgabe zusätzlich übernehmen. Neben der Messeinteilung für die Herstellung von Kaffee z.B. einem halben Liter (bis zu 3 Tassen) und einem Liter für (bis ca. 6 Tassen), kann das Wasserreservoir dann eine weitere Mengeneinteilung aufweisen und könnte somit, ggf. mit einer geeigneten Ausgussnase versehen, als Messgefäß für Flüssigkeiten und auch für Schüttgut eingesetzt werden.
• 6. Damit Hörbehinderte problemloser das Ende der Kaffeezubereitung wahrnehmen, kann zu dem akustischen noch ein optisches Signal aktiviert werden.
• 7. Um nur ein Kaffeemaschinen-Chassis sowohl für Thermokannen als auch für eine Glaskannen einsetzen zu können, kann die Kannenstellfläche der Kaffeemaschine so konstruiert werden, dass z.B. durch Entfernen eines Blinddeckels eine Warmhalteplatte eingesetzt werden kann. Beide Optionen, sowohl Glaskanne als auch Isolierkanne einsetzen zu können, sind auf diese Weise mit einem Kaffeemaschinengehäuse möglich
• 8. Zur weiteren Vereinfachung der Kaffeemaschinen-Produktion ist es sinnvoll, wenn der Handgriff zum Abnehmen des Wasserreservoirs mit dem Griff der Kanne hinsichtlich Form, Material und Abmaßen identisch ist.

Further improvements in production and provision:

• 1. Since in conventional coffee machines, the heat through the hot plate regardless of the amount of coffee to be kept warm is always the same, it is proposed to protect the coffee aroma, in addition to the individual adjustability to adjust the holding temperature of the respective amount of coffee.
• 2. Furthermore, for example, by a display installed in the can handle both the coffee temperature and the amount of coffee, how many cups are still available in a thermos, would be displayed continuously, at intervals or retrievable.
• 3. When using a capacitor or electric accumulator and / or with the help of the Peltier effect, the electrical energy for the display of the coffee temperature and amount of coffee can be permanently ensured without cumbersome battery replacement.
• 4. If the coffee beverage has to be stored for a long time, it makes sense for the vacuum jug to make the can bottom heat-permeable and to compensate for the heat loss by means of a very low heat input.
• 5. Because liquid quantities are often measured in the kitchen, the removable water reservoir can take on this task in addition. In addition to the fair division for the production of coffee, for example, half a liter (up to 3 cups) and a liter for (up to 6 cups), the water reservoir can then have a further quantity division and could thus, if necessary provided with a suitable spout nose, used as a measuring vessel for liquids and also for bulk material.
• 6. In order to make it easier for the hearing impaired to perceive the end of the coffee preparation, an optical signal can be activated for the acoustic signal.
• 7. In order to use only a coffee machine chassis both for thermal jugs and for a glass jugs, the can foot rest of the coffee machine can be designed so that, for example, by removing a blind cover, a hot plate can be used. Both options, both glass jug and vacuum jug to use, are possible in this way with a coffee machine housing
• 8. To further simplify the coffee machine production, it makes sense if the handle for removing the water reservoir with the handle of the pot is identical in terms of shape, material and dimensions.

The Measuring methods according to the invention are also used to detect errors in the preparation of coffee. So it comes for example. in front. that the filled filter approximately when swinging of the filter housing is deformed into the coffee maker, so a not inconsiderable Amount of water outside the filter flows into the pot, without flowing through the ground coffee. The result is that the coffee initially flowing into the pot already very diluted by this amount of water. If by the measuring method it is determined that the coffee concentration initially too is weak and not one for can achieve the flawless coffee preparation expected value, the Preparation interrupted and about an alarm signal are issued.

1

Wasserreservoir

2

Rückschlagventil

3

Schalter

4

Niederspannungstransformator

5

Steuermodul

6

Kontakt

7

Einstelleinrichtung (Kaffeekonzentration)

8

Kannenfuß

9

Lichtdiode

9b

Transistor

10

Elektrische Anschlüsse

11

Kannengriff

12

Kannenbehälter

13

Schließventil

14

Kaffeefilter

15

Heißwasserzuleitung

1 . 2 . 3

1

water reservoir

2

check valve

3

switch

4

Low voltage transformer

5

control module

6

Contact

7

Adjustment device (coffee concentration)

8th

Kannenfuß

9

light emitting diode

9b

transistor

10

Electrical connections

11

can handle

12

can container

13

closing valve

14

coffee filter

15

Hot water supply

16

Positionierungskonus

17

Rinne für Restmengen

18

Glaskörper mit Reflektionsspiegel

19

Lichtdetektor (Empfänger)

20

Laser-Lichtdiode

21

Glassteg (ringförmig)

22

Nach innen gewölbter Kannenboden

23

Spiegelfläche

24

Lichtdetektor, alternativ zum Spiegel

4 . 5 . 6 . 7

16

positioning cone

17

Gutter for residual quantities

18

Vitreous body with reflection mirror

19

Light detector (receiver)

20

Laser light diode

21

Glass web (ring-shaped)

22

Inwardly curved can bottom

23

mirror surface

24

Light detector, alternative to the mirror

25

Kannenboden (Glas)

26

Grenzfläche Kannenboden/Kaffeegetränk

27

Lichtstrahl

28

Reflektionsspiegel

29

Lichtleiterkabel

30

Steckadapter für Kannenfuß

31

Optisches Kannenfenster

32

Sockel (Kaffeemaschine)

33

Laserlicht

8th . 9 . 10

25

Can bottom (glass)

26

Kannenboden / Kaffeegetränk interface

27

beam of light

28

reflection mirror

29

Optical fiber cable

30

Plug adapter for can foot

31

Optical can window

32

Base (coffee machine)

33

laser light

Claims (18)

A method for preparing beverages of desired concentration, wherein the concentration correlates with the translucency of the beverage, in particular for preparing coffee by means of a coffee machine, in which light is irradiated in the light, the light attenuated by the drink is interrupted and the preparation process is interrupted, if the measured value of the attenuated light reaches a predetermined desired value, characterized in that the Drink scattered light of the incident light is measured and the preparation of the beverage is interrupted upon reaching the predetermined target value. Process for preparing beverages of desired concentration, wherein the concentration correlates with the translucency of the beverage, in particular for preparing coffee by means of a coffee machine, wherein the drink Light is being measured, the light attenuated by the drink and the preparation process is interrupted when the measured value of the weakened Light reaches a predetermined target value, characterized that light on a transparent interface behind which the drink is located and the one higher Refractive index as the drink has at an angle greater than the total reflection effect critical angle of incidence, with a portion of the radiation in the drink absorbs the intensity of the reflected light measured and at a given setpoint of the measured intensity the preparation of the beverage is interrupted. Method according to claim 2, characterized in that that the light reflected at the boundary layer is repeatedly applied to the Boundary layer is reflected back, before the intensity of the multiply reflected light is measured. Process for preparing beverages of desired concentration, wherein the concentration correlates with the translucency of the beverage, in particular for preparing coffee by means of a coffee machine, wherein the drink Light is being measured, the light attenuated by the drink and the preparation process is interrupted when the measured value of the weakened Light reaches a predetermined target value, characterized that the light in the drink radiated and this leaves after a short distance and that this weakened Measured light and upon reaching a predetermined setpoint the Preparation of the beverage is interrupted. Method according to one of the preceding claims, characterized characterized in that during a preparation of the beverage a ground substance and a liquid, especially water, more liquid to disposal is posed as for the preparation of the beverage necessary is. Method according to one of the preceding claims, characterized characterized in that when the predetermined setpoint is not reached will, the preparation of the drink is interrupted. Method according to one of the preceding claims, characterized in that, when measured at the beginning of the preparation of the beverage Value does not reach a predetermined second set point, the preparation of the beverage interrupted becomes. Method according to one of claims 6 or 7, characterized that when one of the setpoints is not reached, an alarm signal is delivered. beverage maker to carry out of the method according to claim 1, in particular for the preparation of Coffee by means of a coffee machine, the drink in one at least partially transparent container is received, - with a Transmitter for injecting light into the drink, - with a receiver for Receiving the drink attenuated Light of the transmitter and - With a control module that evaluates the readings of the receiver and on reaching a predetermined target value interrupts the preparation of the beverage, thereby characterized in that sender and receiver are adjacent outside of the container located and arranged so that the recipient of the scattered by the drink Scattered light of the incoming light receives. Beverage container after Claim 9, characterized in that transmitter and receiver outside of the container are arranged. beverage maker according to claim 9 or 10, characterized in that the center line the irradiation direction of the transmitter and the center line of the receiving direction Recipient take an acute angle with each other. beverage maker according to claim 9 or 10, characterized in that the center line the irradiation direction of the Sen and the center line of the receiving direction Recipient are essentially parallel. beverage maker according to one of claims 9 to 12, characterized in that transmitter and receiver in a handle of the container of the beverage maker are arranged. beverage maker according to claim 13, characterized in that transmitter and receiver in the handle are arranged in the region of the bottom of the container. Beverage maker according to one of claims 9 to 12, characterized in that transmitter and Receiver are arranged in a bottom of the beverage maker, on which the container is seated. Device according to one of claims 9 to 15, characterized the transmitter is a laser transmitter, in particular a laser diode. beverage maker according to one of claims 9 to 15, characterized in that the receiver is a transistor, in particular a CMOS transistor is. Beverage maker, in particular for preparing coffee by means of a coffee machine, being the drink is received in an at least partially transparent container, - with a Transmitter for injecting light into the drink, - with a receiver for Receiving the drink attenuated Light of the transmitter and - With a control module that evaluates the readings of the receiver and on reaching a predetermined target value interrupts the preparation of the beverage, thereby characterized in that the container at least in the area of its footprint is transparent and a arched inwards Has bottom so that a peripheral edge is formed, and that the transmitter this edge radiates through and the receiver passes through the edge blasted light, if necessary after reflection and re-radiation of the edge, receives.