METHOD FOR DOSING HOP PELLETS INTO A FERMENTED BEER PRE-PRODUCT AND APPARATUS FOR EXECUTING THE METHOD

Description

[0001] The present invention relates to a method for dosing hop pellets into a fermented beer precursor, for example a green beer, and a plant for carrying out the method.

[0002] Currently, various methods of so-called cold hopping are known, although the majority of production processes are limited to manually adding the hops to the cold storage tank before filling it with a beer precursor.

[0003] Alternative processes, such as those disclosed in US Pat. No. 8,875,616 B2, describe the extraction of hop pellets in a separate container, yielding a hop extract that must then be added back to the beer. The hops are thus only dissolved in a portion of the beer stream. In addition, grinding the hop pellets is often included to increase the extraction of the aroma components.

[0004] The process of so-called dry hopping is described, among others, in DE 10 2015 121 999 A1, DE 2 228 497 A, and GB 2 531 054 A. In most of these processes, however, hopping takes place at a comparatively early stage of beer production, which is usually followed by a temperature-intensive fermentation.

[0005] This process is most succinctly described in GB 2 531 054 A, in which the hop addition is heated to temperatures above 80°C during and after hopping.

[0006] DE 2 225 375 A1 teaches a method for feeding hop granules to a brew kettle and a device for this purpose. The granules are portioned and crushed using a rotary valve. The crushed granules are then transported into the brew kettle using water or wort.

[0007] DE 10 2013 101 435 A1 discloses a device for extracting aroma substances from beer. For this purpose, a device consisting of a sequence of several process containers is disclosed.

[0008] Based on the aforementioned prior art, the object of the present invention is to provide a method which enables the dosage of lupulin-containing hop pellets into a beer precursor in a manner which preserves the aroma substances.

[0009] The present invention solves this problem by providing a method having the features of claim 1 and by a system having the features of claim 19.

[0010] The method according to the invention relates to the dosing of hop pellets into a fermented beer precursor. This is a step in the production of beer, for example, during dry hopping.

[0011] The process according to the invention is carried out using a system comprising a dosing system and a pump. It comprises the following steps. I. Feeding hop pellets into the system; II. Dosing a predetermined amount of hop pellets from the dosing system to the pump; III. Feeding the predetermined amount of hop pellets into a line carrying the beer precursor or a tank filled with the beer precursor via the pump.

[0012] The process according to the invention can optionally be supplemented by the following step: IV. Clarifying the beer provided with pelleted and / or granulated hops by means of mechanical separation technology, in particular by a filtration device and / or a centrifuge,

[0013] Between steps III and IV, the beer can also be stored and / or matured.

[0014] The dosed hop pellets are fed into the line carrying the beer precursor or into the tank filled with the beer precursor in pelletized and / or granulated form.

[0015] By adding the granulated and / or pelletized solids to the beer precursor in a lumpy manner with low shear force, particularly without prior extract formation, ingredients such as lupulin granules are transferred into the liquid undamaged.

[0016] When fed into a line carrying beer precursor, a uniform and rapid distribution of the hop pellets and their ingredients in the beer precursor can be achieved in a particularly advantageous manner.

[0017] The flow rate of the beer precursor, especially the pumping time, in the line can be adjusted to the dosing. The minimum pump operating time (t Pump ) should preferably be longer than the dosing time (t Dos. ).

[0018] Particularly preferred is: t Dos. ≤ 0.95 t Pump

[0019] The addition of hop pellets to a tank filled with beer precursor is also possible. "Filled" can also, particularly preferably, mean that the tank is partially filled, i.e., not completely filled.

[0020] It is recommended to equip the tank preferably with one or more stirring devices so that the added hop pellets or hop granules can be better distributed.

[0021] The fermented beer precursor can, in particular, be green beer. A beer precursor is not yet considered a finished beer, but rather an intermediate product in beer production.

[0022] The process according to the invention can thus comprise further steps, although the temperature before hops are separated from the beer precursor, and particularly preferably also not during all further brewing steps, does not exceed a temperature of 60°C, preferably 30°C, at any time.

[0023] Further advantageous embodiments of the invention are the subject of the subclaims.

[0024] It is advantageous if at least 30% by weight, preferably at least 50% by weight, particularly preferably at least 80% by weight of the hop pellets introduced into the system are in pelletized and / or granulated form with an average grain size having an equivalent diameter of at least 1 mm when the metered hop pellets are fed into the liquid. More than 50%, preferably more than 80%, in particular more than 90% of the metered hop solids in granulated and / or pelletized form have an equivalent diameter of at least 1 mm. Solids in the form of granulated and / or pelletized hop pellets can be present in various grain sizes above this equivalent diameter.

[0025] This makes it possible for the hop pellets to be coarsely ground in the plant. However, this coarse grinding process does not produce a powder, but rather a granulated solid with the appropriate grain size.

[0026] The hop pellets can be fed dry or, more preferably, in a liquid into the line carrying the beer precursor or into the tank filled with the beer precursor.

[0027] The clarification in step IV can preferably be carried out by filtration or also preferably by centrifugal clarification.

[0028] Maturation and storage can take place between the addition of the dosed hop pellets and clarification.

[0029] The pelleted and / or granulated form of the hop pellets can be retained, so that the liquid serves to facilitate the transport of the hop pellets in the plant.

[0030] The temperature of the beer precursor in the line carrying the beer precursor or in the tank filled with the beer precursor should be less than 60°C, preferably less than 30°C. This ensures that the hop constituents are added and processed very gently. For this purpose, a temperature sensor can be provided in the line carrying the beer precursor or in the tank. The measurement signal from the temperature sensor can be compared via a control and / or evaluation unit using an actual value / setpoint comparison. If the temperature of the beer precursor is too high, the dosing of hop pellets can be stopped. The beer precursor can be cooled via a cooling circuit and fed back into the system. Temperature-controlled dosing can also prevent the occurrence of undesirable changes in flavor.

[0031] The system can advantageously have a first container which is arranged in front of the dosing system in the transport direction of the hop pellets.

[0032] The system may also comprise a second container which is arranged between the dosing system and the pump.

[0033] The containers allow for a more optimized addition, especially a more uniform addition, of hop pellets.

[0034] The dosing speed can be advantageously determined by controlling the pump.

[0035] The process is best applied at a very late stage of the brewing process, namely after the primary fermentation. Thus, the beer product to be hopped is a pre-fermented beer product that has already fermented. This late stage is relatively unusual, but it has been found that special flavor effects can be achieved by hopping at this late stage. Any secondary fermentation during the subsequent maturation at a temperature below 60°C does not affect this effect.

[0036] During the process, an inert gas can be introduced into the dosing system, the first and / or second container. This advantageously prevents unwanted contact of certain gases with the hop pellets, such as oxygen.

[0037] Particularly preferably, at least the dosing system or the second container can be overlaid with inert gas and thus preferably pressurized.

[0038] After the metered hop pellets have been added, the system can be cleaned using liquid or vaporous cleaning fluid. CIP cleaning is particularly preferred.

[0039] Cleaning may involve supplying dry air after cleaning with liquid or vaporous cleaning fluid. This dries the system.

[0040] The dosing of the hop pellets can be carried out by the dosing system at least through a cell wheel. The component of the system that includes the cell wheel is called a cell wheel lock. The rotation speed of the cell wheel can also be controlled via the aforementioned control and / or evaluation unit depending on the stirring speed of an agitator in the tank or the flow rate of the beer precursor in the line.

[0041] The exact quantity / time dosing of the hop pellets is achieved by regulating the cell wheel speed.

[0042] The line carrying the beer precursor can be equipped with a flow regulator and a flow meter for monitoring and adjusting the flow of the beer precursor in the line. The same can also be implemented in the variant with the tank and the beer precursor filled therein, although in this case the agitator speed of the agitator in the tank is monitored.

[0043] In the case of a tank instead of a pipe, the quantity of hop pellets can also be determined based on the fill level of the beer precursor in the tank.

[0044] The pump can be designed for gentle conveying, wherein a rotor and a stator of the pump are arranged such that the granulated and / or pelletized form of the hop pellets is retained in at least 90% by weight of all hop pellets.

[0045] The fill level of the first and / or second container is monitored by a fill level measurement and / or monitoring device, e.g. by fill level limit switches, which enables functional monitoring of the rotary valve.

[0046] In addition to the measured addition of hop pellets, wood chips can also be added to the beer precursor. The cell wheel can also be used for this purpose. The wood chips give the beer a special lager flavor, such as that of oak barrels. However, the addition of wood chips is not necessary for every beer type.

[0047] Hop pellets can advantageously have a higher lupulin content compared to natural hop cones of the same weight. Alpha-lupulin content, in particular, can be advantageously increased. These aromatic compounds are particularly important for the flavor characteristics of the beer. A higher proportion of these aromatic compounds combined with a reduced volume facilitates addition during solids dosing and also allows for better transport of the hops and reduced storage costs.

[0048] Also according to the invention is a system for carrying out a method according to the invention, wherein the system a) a first container b) a dosing system for dosing the solids c) a second container and d) a pump which is connected to a liquid-carrying line, in particular a beer precursor-carrying line.

[0049] A particular advantage of the process is that pelletized and / or granulated solids are not broken up.

[0050] Even when liquid is added to support the transportability of the solid, the solid does not dissolve and extract is not formed, but the solid remains largely in a granulated and / or pelletized form.

[0051] The pump can preferably be designed as a positive displacement pump with two inlets, one inlet being designed for supplying hop pellets and one inlet being designed for supplying beer precursor, and one outlet being designed for discharging a product from the hop pellets and the beer precursor.

[0052] The invention is explained in more detail below using a specific embodiment and with the aid of the accompanying figures. It shows: Fig. 1 schematic representation of a process for producing beer; and Fig. 2 schematic representation of an arrangement for cold hopping beer.

[0053] Fig. 1 shows a beer production process, where additional optional steps may be included. A first step of the Fig. 1 The process described involves crushing the malt 101.

[0054] Mashing 102 then takes place. This involves breaking down the grist for further processing.

[0055] After mashing (102), the mixture is lautered (103). This separates the mash and wort.

[0056] The next step is boiling, also known as wort boiling. This involves denaturing malt enzymes, among other things. Hops are often added during this step.

[0057] The mixture is then cooled 105.

[0058] The addition of yeast then initiates fermentation, in which the wort is converted into alcohol and carbon dioxide. The resulting mixture is often called "young beer."

[0059] After fermentation 106, the young beer is stored and / or matured 107. Prior to this, the hop pellets 108 are added according to the invention at a relatively late stage of the beer production process.

[0060] After storage and / or maturation 107, the beer is filtered 109 to remove protein tannins, hop components, e.g. hop resin substances, and other young beer components.

[0061] Finally, the produced beer is bottled.

[0062] The addition of the hop pellets in step 108 can be carried out in a plant 1 as described in Fig. 2 shown.

[0063] Annex 1 of the Fig. 2 has a supply line 2 for hop pellets 200.

[0064] The hop pellets 200 are introduced into a first container 3. The first container 3 or a mass transfer line 6 arranged on the first container 3 has a first supply line and / or a discharge line 4 for an inert gas 300. Furthermore, the first container 3 has the mass transfer line 6 arranged on the container and / or the supply line 4 for an inert gas 300 and / or a supply line 5 for dry air 400. The container 3 can also be understood as a buffer container. Due to the solids column, this allows a continuous flow of solids to a downstream solids dosing system.

[0065] The material transfer line 6 is used for the transfer of hop pellets and can also be designed independently of the supply lines 4 and 5.

[0066] On or in the supply line 5 for dry air there may be a drying unit 7 for introduced air in order to remove residual moisture.

[0067] The material transfer line 6 leads into the dosing system 8. This can be configured, for example, with a so-called rotary valve. Alternatively or in addition to such a rotary valve, a system of alternately controlled valves or slides for solid dosing can be provided.

[0068] The dosing system 8 doses hop pellets in granulated and / or pelletized form into a container 9. The container 9 or a mass transfer line 10 opening into the container has, if required, a second supply line 11 for inert gas 300.

[0069] The material transfer line 10 opens into a pump 12, which can be designed as a positive displacement pump. The pump 12 is arranged along a beer line 13, with section 13a of this line supplying the beer precursor to the pump 12 and section 13b of the line being connected to the pressure side of the pump and discharging the beer, now containing the added hops. A feed regulator in the control system ensures the correct dosage of the hop pellets 200 into the beer precursor. For this purpose, the amount of green beer (volume / time) is determined, for example, in a flow measurement 14, which then serves as a reference variable for the speed controls of the pump 12 and the rotary valve 8. As an alternative to this quantity-proportional dosage, a time-proportional dosage can also be used.

[0070] The beer product line also features a temperature sensor 15, which monitors the temperature of the beer precursor. If this temperature is too high, hopping does not occur. However, cooling of the beer precursor can be initiated. Not shown, but easily conceivable, a control and evaluation device could be used to control the individual process steps and for process monitoring.

[0071] The pump 12 is preferably designed as a positive displacement pump. It serves both to supply hops on the suction side and to supply the beer precursor between the suction side and the discharge side of the pump. The product is discharged from the pump as hopped beer on the discharge side. Typically, a positive displacement pump comprises an impeller and a stator. In the present pump, both the impeller and the stator are designed to be low-shear. The pump thus comprises two inlets, preferably a solids inlet and a liquid inlet, and an outlet, preferably a liquid outlet. One of the two inlets can preferably be arranged between the suction and discharge sides of the pump 12.

[0072] The added hop pellets largely retain their pelleted form during dosing and feeding, so that lupulin grains are not destroyed during dosing.

[0073] Hop pellets can be added to beer in a preferred size range of 1 mm to 20 mm. This hop pellet addition to beer represents a critical point in the brewing process, as it poses the risk of food contamination, CO2 degassing, and / or oxygen ingress.

[0074] With the invention presented here, aroma carriers from the hop pellets can be introduced into a volume flow automatically, without oxygen input, without CO2 discharge and / or hygienically.

[0075] The container 3 can be loaded manually or automatically, or can hold a predetermined amount of a product batch. The container can then be sealed and pressurized with a gas, particularly an inert gas, thus pre-pressurizing it to prevent oxygen from being absorbed or carbon dioxide from being lost from the green beer.

[0076] Preferably, the second container 9 has an outlet flange which is flanged to an inlet of the pump 12 so that the hop solids can freely fall into the inlet of the pump 12.

[0077] The pump may preferably be designed as a positive displacement pump and particularly preferably as an eccentric screw pump or twin-screw spiral pump.

[0078] If necessary, the vessel 9 can be pre-pressurized with an inert gas to reduce or completely eliminate the oxygen content in the system and to maintain the CO2 content of the beer. The pressure side of the pump 12 is connected to the liquid product line, for example, the beer line 13b. The vessels 3 and / or 9 can be equipped with level measurement sensors; the fill level can be determined using, for example, ultrasound, conductivity, capacitance, or radar.

[0079] System 1, particularly tanks 3 and 9, can be cleaned by introducing a cleaning fluid, e.g., water. This can also be done using steam. Cleaning can be performed as part of a CIP cleaning process. It is advisable to dry the system with dry air after cleaning. The drying unit is provided for this purpose, which draws in and dries filtered outside air.

[0080] The solid is dosed into the container 9 via the dosing system 8, the function of which can be monitored via the level measurements.

[0081] This allows for preferential determination of whether hop pellets are being conveyed into container 9. If no increase in level is detected despite the conveyance through the cell wheel, a blockage of the cell wheel, for example, can be output as an error message.

[0082] This allows the dosage to be monitored based on the fill level. Dosing from container 9 into the product stream can be achieved by pump 12 receiving the dry solids and conveying them into the beer line 13b. To prevent wear, a small product flow is fed to the pump inlet, or in the case of an eccentric screw pump, to the stator inlet.

[0083] Dosage can also be carried out with moistened solids. However, this retains its granulated or pelleted form.

[0084] The preferred method is Fig. 2 shown in Appendix 1 for the so-called cold hopping, i.e. the addition of hops to already fermented beer precursor, the so-called young beer 500. By adding granulated or pelleted hops, the aromas contained in the hops remain in the hopped beer 600 and thus give the beer a special aroma.

[0085] Cold hopping is preferably carried out at temperatures below 60°C, preferably below 30°C. Unlike warm hopping, for example, in copper kettles at boiling temperature, cold hopping produces fewer bitter substances or other by-products.

[0086] A particularly suitable beer for green beer 500 is a pre-clarified beer to which hop pellets, possibly in partially crushed form, have been gently added for flavoring in granular and / or pellet form. These hops, which are added to the beer in a granular form, should be removed from the beer as a solid after addition and after a certain exposure time, preferably by clarification, e.g., using a centrifuge or a separator.

[0087] As an alternative to a centrifuge, a filtration device can be used to clarify the beer or remove the added hop solids. Alternatively, separation can also be achieved through natural sedimentation.

[0088] Thus, the mixture of beer and hop components can be advantageously clarified.

[0089] Hops 200 are fed from supply line 2 into beer line 13 without any grinding or solids reduction device. This allows for non-destructive addition of the hops to the beer in pelleted or granulated form, preventing damage to aroma carriers.

[0090] In the cold hopping process, these aroma carriers are, for example, the lupulin granules, which contain the aromatic substances and bitter substances of the hops and are found in concentrated form, especially in hop pellets.

[0091] System 1 is used primarily for dosing solids into liquids, whereby the structure of the solids should be preserved during dosing. Grinding or shearing of the solids should not occur, so that the dissolution or leaching of these solids only occurs in the suspending liquid, e.g., in beer.

[0092] It is also possible to add a liquid, particularly the same liquid into which the solid is to be dosed, to improve the removal of the granulated and / or pelletized solids from the container 9. As an example, the device is described here in the context of dosing hop pellets into beer. A quantity of beer, usually a comparatively small quantity, can be added to the granulated and / or pelletized hops, thereby improving the removal of the solids from the container 9 into the pump 12. Alternatively, only a residual amount of solids can be removed by rinsing.

[0093] The pelleted and / or granulated form remains essentially intact even when beer is added for about 1 minute, better about 2 minutes, even better about 5 minutes for the purpose of transfer.

[0094] Granulated raw materials are raw materials pressed or ground into small beads. Pellets are pressed into an elongated, cylindrical shape. Granules are usually free-flowing solids. Pellets, on the other hand, are usually larger than granules.

[0095] The clarification / filtration according to step 109 can be carried out in a process for clarifying a flowable product, similar to that described in DE 10 2013 111 579 A1. This process is incorporated by reference for the advantageous clarification of beer and other liquids containing solids. This clarification can advantageously follow the inventive process for dosing solids or be integrated into the inventive process as an additional process step after the solid is introduced into the liquid.

[0096] The addition of lupulin-enriched hop granules or lupulin-enriched hop pellets is particularly preferred.

[0097] During the enrichment process, the leaf fraction and the umbel spindle were removed, resulting in an enrichment in lupulin.

[0098] These can be obtained from hop cones through a multi-stage processing process. A preferred production process for hop pellets includes at least the following steps. The steps marked "if necessary" are merely optional steps that can be performed individually or in combination with other optional steps: I. Providing the hop cones II. If necessary, removing stems and leaves III. Drying, preferably at less than 65°C, to reduce the moisture content in the hops, preferably to less than 11 percent by weight or % w / w, preferably less than 8 percent by weight; IV. Cooling to temperatures of less than minus 25°C; V. Grinding to produce a powder, e.g. in a hammer mill; VI. If necessary, sieving to separate a leaf fraction; VII. If necessary, homogenizing the powder, preferably in powder mixing devices; VIII. Pelletizing in a press, preferably at temperatures below 55°C; VIII. If necessary, cooling to temperatures of less than 20°C IX. Depending on the time of use, if necessary, packaging the pellets with exclusion of oxygen, preferably under an inert gas atmosphere, in particular nitrogen and / or carbon dioxide.

[0099] The preferred hop pellets and / or granules have a preferred density of more than 400 kg / m 3 , in particular a density of 480 to 550 kg / m 3 . In contrast, hops in cone form, i.e. not in granulated or pelleted form, have a density of 130 to 150 kg / m 3 , which, among other things, makes dosing the hops more difficult.

[0100] The hop pellets preferably used can preferably contain between 6 and 20 wt.% of so-called alpha acids.

[0101] The hop pellets preferably used can preferably contain between 6 and 15 wt.% of so-called beta acids.

[0102] The preferred hop pellets can preferably contain between 0.5 and 4 ml / 100g of so-called essential oils. List of reference symbols

[0103] 1System 2Inlet 3Vessel 4Inlet and / or outlet 5Inlet 6Mass transfer 7Drying unit 8Dosing system 9Vessel 10Mass transfer 11Inlet 12Pump 13Beer precursor-carrying line 14Flow measurement 15Temperature sensor 101Grinding the malt 102Mashing 103Lautering 104Boiling 105Cooling 106Fermenting 107Aging / Storage 108Adding hop pellets 109Clarifying / Filtering 110Bottling 200 hop pellets 300 inert gas 400 dry air 500 green beer 600 hopped beer

Claims

1. A method for metering hops pellets (200) into a fermented beer precursor in order to produce beer, with a plant (1) comprising a metering system (8) and a pump (12), wherein the method is characterized by the following steps: I. supplying hops pellets (200) into the plant (1); II. metering a predefined quantity of hops pellets from the metering system to the pump (12); III. introducing the specified quantity of hops pellets (200) from II. into a line (13) carrying beer precursor or into a tank filled with beer precursor by means of the pump (12), wherein the metered hops pellets (200) are introduced in pelletized and / or granulated form into the line (13) carrying beer precursor or into the tank filled with the beer precursor, and wherein the temperature of the beer precursor in the line (13) carrying beer precursor or in the tank filled with the beer precursor is less than 60°C.

2. The method as claimed in claim 1, characterized in that the beer containing the pelletized and / or granulated hops is clarified by means of the mechanical separating technique, in particular by a filtration device and / or a centrifuge.

3. The method as claimed in claim 1 or 2, characterized in that when the metered hops pellets (200) are introduced into the beer precursor, at least 30 w.%, preferably at least 50 w.%, particularly preferably at least 80 w.% of the hops pellets (200) introduced into the plant (1) are present in pelletized and / or granulated form with a mean grain size of at least 1 mm, wherein the hops pellets (200) have a higher lupulin content than natural hop cones with the same weight..

4. The method as claimed in any of the preceding claims, characterized in that the hops pellets (200) are introduced in dry state into the line (13) carrying beer precursor or into the tank filled with beer precursor.

5. The method as claimed in any of the preceding claims 1 - 3, characterized in that the hops pellets (200) are introduced in a liquid into the line (13) carrying beer precursor or into the tank filled with beer precursor.

6. The method as claimed in any of the preceding claims, characterized in that the temperature of the beer precursor in the line (13) carrying beer precursor or in the tank filled with the beer precursor is less than 30°C.

7. The method as claimed in any of the preceding claims, characterized in that the beer precursor is a fermented beer precursor ore a green beer (600) in a beer production process.

8. The method as claimed in any of the preceding claims, characterized in that the plant comprises a first container (3) which is arranged upstream of the metering system (8) in the transport direction of the hops pellets (200).

9. The method as claimed in any of the preceding claims, characterized in that the plant (1) comprises a second container (9) which is arranged between the metering system (8) and the pump (12).

10. The method as claimed in any of the preceding claims, characterized in that during the method, an inert gas (300) is introduced into the metering system (8), the first and / or the second container (3, 9, wherein the hops pellets (200) particularly preferably are overlaid with inert gas (300) at least in the metering system (8) or in the second container (9).

11. The method as claimed in any of the preceding claims, characterized in that the method comprises a cleaning of the plant (1) following the supply of the metered hops pellets (200), wherein the cleaning takes place with one or more liquid or vaporous cleaning fluids, wherein the cleaning particularly preferably comprises the introduction of dry air after cleaning with liquid or vaporous cleaning fluid.

12. The method as claimed in any of the preceding claims, characterized in that the hops pellets (200) are metered by the metering system (8) by means of at least one rotary feeder, wherein the dosage of the hops pellets (200) particularly preferably are metered by controlling the rotation speed of the rotary feeder, in particular depending on a mean throughflow of the beer precursor in the line carrying the beer precursor, or depending on the agitation speed of the beer precursor in the tank filled with beer precursor.

13. The method as claimed in any of the preceding claims, characterized in that the pump (12) is designed for gentle delivery, wherein a rotor and a stator of the pump (12) are arranged such that the granulated and / or pelletized form of the hops pellets is retained for at least 90 w.% of all hops pellets (200).

14. The method as claimed in any of the preceding claims, characterized in that the fill level of the first and / or second container (3, 9) is monitored by fill level meter, a pressure meter and / or a fill level limit switch.

15. A plant (1) for carrying out a method as claimed in claim 1, characterized in that the plant (1) comprises a) a first container (3) for receiving hops pellets, b) a metering system (8) for metering these hops pellets into c) a second container (9), and d) a pump (12) which is fed from the second container (9) and on the pressure side is connected to a liquid-carrying line (13b), in particular a line carrying beer precursor, or to a tank filled with a beer precursor, wherein the metering system (8) comprises a rotary feeder which is controlled such that hops pellets are metered into the beer precursor only when the beer precursor temperature is less than 60°C.