Method for performing a fermenting process and apparatus for performing said method

Abstract

Method for performing a fermenting process and Apparatus for performing said method, wherein the method for performing a fermenting process in a fermentation vessel, comprising: supplying a yeast suspension into the fermentation vessel (S1), fermenting, during the fermentation process, the yeast suspension within the fermentation vessel (S2), wherein, during the fermenting process, yeast can accumulate in a lower portion of the vessel, and, during at least part of the fermentation process, carrying out a recirculating process in an at least quasi- continuous or continuous manner (S3), which recirculating process comprises: withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel (S31), separating the withdrawn yeast suspension by means of a separating device to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate (S32), and recirculating the permeate into the fermentation vessel (S33).

Description

[0001] P93096

[0002] 1

[0003] METHOD FOR PERFORMING A FERMENTING PROCESS AND APPARATUS

[0004] FOR PERFORMING SAID METHOD

[0005] Field of the invention

[0006] The present invention relates to a method for performing a fermenting process, and an apparatus for performing a fermenting process.

[0007] Background of the invention

[0008] In fermentation processes (e.g., production of a yeast-fermented drink such as beer, honey wine, or kombucha), approximately 3 % of the total volume may be accrued as yeast. This yeast is usually accumulated at the bottom of a fermentation vessel at the end of the fermentation process. Due to high viscosity and, hence, insufficient liquid movement, of the accumulated yeast, the accumulated yeast in the lower portion of the vessel is not uniformly cooled and is not cooled sufficiently low even if cooling zones are installed.

[0009] For example, in a case of a cylindroconical vessel (CCV), a central volume of a conical portion is heated considerably above a desired temperature. At the same time, the accumulated yeast in the conical portion of the CCV suffers from lack of nutritive medium during a sedimentation process, because the content of the yeast suspension is increased there due to the higher specific weight of the yeast. Autolysis happens to most of the accumulated yeast, the cell wall of the yeast cells opens, and the content of the cells is discharged into and mixed with the yeast suspension.

[0010] Therefore, the accumulated volume at the lower part of the fermentation vessel has traditionally been discarded, in spite of the accumulated yeast containing a significant amount of fermented product (e.g., the dry mass content of the accumulated and sedimented volume at the end of a beer fermentation process is approximately 8 to 12 %, the remaining liquid part being fermented wort).

[0011] If recovery of the fermented product from the accumulated yeast is performed at all in modem fermentation processes (e.g., in modem breweries), the accumulated yeast P93096

[0012] 2 containing residual amounts of fermented product is guided to a separate vessel at the end of the fermenting process, and further processed therefrom in a separate separation process conducted non-continuously and independently from the fermenting process (e.g., by separators, decanters).

[0013] In addition, the fermented product recovered in such a non-continuous manner is of inferior quality due to above-mentioned autolysis products contained therein (e.g., these autolysis products may result in negative taste components).

[0014] Hence, e.g., in case the fermented product is a yeast-fermented drink, the fermented product recovered in this manner is of inferior quality (e.g., it is only rarely used for premium brands in case of beer production). Thus, in such a case, the product recovered from the accumulated yeast could only be diluted in small amounts to nonrecovered product so as to dilute it and its negative taste components therein.

[0015] However, the autolysis products (e.g., the negative taste components) can still be detected analytically, and they can often even be perceived in a sensory manner in the case of a yeast-fermented drink (e.g., when consuming the yeast-fermented drink).

[0016] EP 2 027 244 B1 describes a method for performing a fermenting process, in which fermented product is separated from yeast by means of sedimentation, and the yeast separated by sedimentation is reused for fermentation.

[0017] BRIEF DESCRIPTION OF THE INVENTION

[0018] In the light of the above, it is an objective of the present invention to improve the efficiency of a fermenting process and the quality of the products of the fermenting process.

[0019] To this end, the invention provides a method for performing a fermenting process in a fermentation vessel. The method comprises the step of supplying a yeast suspension (optionally a wort including yeast) into the fermentation vessel. Furthermore, the method comprises the step of fermenting, during the fermentation process, the yeast P93096

[0020] 3 suspension within the fermentation vessel, wherein, during the fermenting process, yeast can accumulate in a lower portion of the vessel. Moreover, during at least part of the fermentation process (optionally during at least for the most part of the fermentation process), carrying out a recirculating process in an at least quasi- continuous or continuous manner, which recirculating process comprises withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel, separating (optionally filtering) the withdrawn yeast suspension by means of a separating device (optionally a filtering device) to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate (the retentate being the extracted yeast retained from the separating) and remaining liquid as permeate (the permeate being the remaining liquid after the separating without the separated extracted yeast), and recirculating the permeate (e.g., recirculating only said permeate (and not the retentate)) into the fermentation vessel.

[0021] The present invention as defined above allows separating (optionally filtering out) the yeast from the yeast suspension during the fermentation (e.g., at the end of the main fermentation). By employing the method, the amount of yeast performing autolysis can be reduced, increasing an efficiency of production, a quality of the fermented product, and a quality of the yeast in the retentate at the same time.

[0022] Herein, the expression “the most part of the fermentation process” may mean above 50% of the time of the fermentation process. For example, said expression may mean above 70% of the time of the fermentation process, optionally, above 90% of the time of the fermentation process. For example, the expression may mean 100% of the time of the fermentation process.

[0023] The recirculating process may be started after a time after a start of the fermentation process.

[0024] Said time may be predetermined or said time may be determined based on at least one characteristic of the yeast suspension within the fermentation vessel. Optionally, said time may be determined based on a detected content of accumulated yeast in the lower portion of the vessel and / or based on a detected alcohol content of the yeast suspension. P93096

[0025] 4

[0026] A delayed start of the recirculating process may allow better targeting the use of the recirculating process to when there is a risk that a significant amount of yeast would otherwise perform autolysis, and, hence, improve an energy efficiency of the fermenting process.

[0027] The separating device may (optionally filtering device) comprise or may be a crossflow filtration device, optionally a dynamic cross-flow filtration device (e.g., a dynamic cross-flow filtration device as described in EP 2 905 067 A1 ).

[0028] The separating device may also comprise or may be a decanter or a decanter centrifuge.

[0029] Due to the higher separation efficiency of the dynamic cross-flow filtration device (DCF) compared to decanters and separators, the market value of the yeast in the retentate may be increased due to an increased concentration of yeast cells per volume. Furthermore, the DCF may require significantly lower amounts of electric energy to be driven compared to a decanter, a separator, or a static membrane filtration machine. Thus, using a DCF as separating / filtering device may lead to higher quality products of fermented product and of yeast retentate (avoiding fermented product with negative taste components, because autolysis does not happen; yeast that is higher concentrated due to higher separation efficiency) and lower costs at the same time (reduced loss as yeast can be better reused and / or resold; the separated yeast does contain less fermented product; reduced energy costs; reduced investment necessary for DCF compared to decanter / separator / (other) membrane filtration devices).

[0030] The suggested process / method also allows for a selective separation of different viable and vital yeast cells, to be used for different subsequent processes. Since less viable cells tend to settle first during fermentation (e.g., at the end of fermentation), it can be separated at first to be disposed or collected for secondary processes. Further, quality of yeast with higher viability and vitality can be separated and collected for subsequent re-use as pitch yeast for next fermentation processes, until P93096

[0031] 5 the needed quantity has been reached. Any additional exceed volumes can be collected and sold as high quality yeast.

[0032] The separating device (optionally filtering device) may comprise a dynamic cross-flow filtration device comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the cross-flow filtration device.

[0033] By employing two vertical rotary shafts, the yeast of the yeast suspension may be enriched along the vertical plug flow slowly moving upwards.

[0034] The fermentation vessel may be a cylindroconical vessel (CCV).

[0035] Using a cylindroconical vessel may allow for a facilitated application of the method, and may make recirculation easier and more efficient, because a CCV has a single lowest point within the vessel for liquid to be stored, thereby facilitating guiding of the suspension to and through the filter.

[0036] The invention further provides an apparatus for performing a fermenting process in a fermentation vessel, wherein the apparatus comprises a fermentation vessel, a suspension supply device, a recirculation line, and a separating device (optionally a filtering device). The fermentation vessel is provided to have an upper vessel portion and a lower vessel portion. The suspension supply device is configured to supply a yeast suspension (optionally a wort including yeast) into the fermentation vessel (optionally into the fermentation vessel via the upper portion thereof). The recirculation line has one end connected to the lower portion of the fermentation vessel to thereby allow to withdraw yeast suspension, including accumulated yeast which may have been accumulated in the lower portion of the vessel, from said lower portion of the vessel, and the recirculation line also has another end connected to a remaining portion (optionally an upper portion) of the fermentation vessel. The separating device (optionally the filtering device) is provided in the recirculation line, which is configured to separate (optionally to filter) the withdrawn yeast suspension to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate. The recirculation line is configured to allow to recirculate the permeate (e.g., to recirculate only said permeate (and not the P93096

[0037] 6 retentate)) into the fermentation vessel via the remaining portion of the fermentation vessel.

[0038] The apparatus as defined above allows separating (e.g. filtering out) the yeast from the yeast suspension during the fermentation. By employing the apparatus, the amount of yeast performing autolysis can be reduced, increasing an efficiency of production, a quality of the fermented product, and a quality of the yeast in the retentate.

[0039] The apparatus may further comprise a pump provided in the recirculating line, and an electronic control device. The pump may be provided in the recirculating line and may be configured to pump the withdrawn yeast suspension from the lower portion of the vessel towards and through the separating device (optionally filtering device). The pump may further be configured to pump the permeate from the separating device (optionally filtering device) back towards and into the fermentation vessel via the remaining portion of the fermentation vessel. The electronic control device may be configured to control the operation of the apparatus in a manner such that, during at least part of the fermentation process (optionally during at least for the most part of the fermentation process), a recirculating process is carried out via the recirculation line in an at least quasi-continuously or continuously manner. The recirculating process may comprise withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel by means of the recirculation line, separating (e.g. filtering) the withdrawn yeast suspension by means of the separating device (e.g. filtering device) to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate, and recirculating the permeate into the fermentation vessel via the remaining part of the fermentation vessel by means of the recirculation line.

[0040] By employing pump and electronic control device as defined above, the apparatus may be controlled to guide the yeast suspension to recirculate, and the apparatus may be enabled to control the recirculating process to be performed only during a part of the fermentation process, and to control the apparatus to perform a continuous or quasi-continuous recirculating process. P93096

[0041] 7

[0042] The control device may further be configured to control the recirculating process in such manner that the recirculating process is started after a time after the start of the fermentation process.

[0043] Said time may be predetermined or said time may be determined based on at least one characteristic of the yeast suspension within the fermentation vessel (optionally based on a detected content of accumulated yeast in the lower portion of the vessel and / or on a detected alcohol content of the yeast suspension).

[0044] The electronic control device may be configured such as to control the apparatus as described in this application in accordance to the method as described in this application.

[0045] The separating device (e.g. filtering device) may comprise or may be a cross-flow filtration device, optionally a dynamic cross-flow filtration device (e.g., a dynamic cross-flow filtration device as described in EP 2 905 067 A1 ).

[0046] The separating device (e.g. filtering device) may comprise a dynamic cross-flow filtration device comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the cross-flow filtration device. The fermentation vessel may be a cylindroconical vessel (CCV).

[0047] The recirculation line, at is one end, may be directly connected to the lower portion of the fermentation vessel, and / or the recirculation line, at its other end, may be directly connected to the remaining portion of the fermentation vessel.

[0048] Direct connection of the recirculation line to the fermentation vessel may ensure a prompt recirculation of the permeate, hence, providing the yeast suspension to spend a higher share of time in the fermentation vessel, which allows for improved efficiency of the fermentation process.

[0049] Further, the invention provides a brewing plant comprising a brew kettle and the apparatus as described in this application. The apparatus is connected to and arranged downstream of the brew kettle. P93096

[0050] 8

[0051] The brewing plant described allows separating (e.g. filtering out) the yeast from the yeast suspension during the fermentation. By employing the brewing plant, the amount of yeast performing autolysis can be reduced, increasing the efficiency of production, the quality of the fermented product, and the quality of the yeast in the retentate.

[0052] The method for performing a fermenting process in a fermentation vessel as described in the present application may be performed using the apparatus as described in the present application and / or the brewing plant as described in the present application. The invention is, however, not limited to the embodiments shown in the drawings and described below, but is defined by the claims.

[0053] BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1 shows a flow diagram of a method according to an embodiment.

[0055] FIG. 2 shows a flow diagram of the method according to the embodiment of FIG. 1 .

[0056] FIG. 3 shows an apparatus for performing a fermenting process according to an embodiment.

[0057] FIG. 4 shows an apparatus for performing a fermenting process according to another embodiment.

[0058] FIG. 5 shows a brewing plant according to an embodiment.

[0059] DETAILED DESCRIPTION

[0060] Herein, the expression “connected” means being directly connected (e.g., fluidly connected) with no other devices or lines present in between except for ports or fittings / adapters, or being indirectly connected with further devices or lines present in between connected parts. P93096

[0061] 9

[0062] Herein, the expression “directly connected” means being directly connected (e.g., fluidly connected) with no other devices or lines present in between except for ports or fittings / adapters.

[0063] Herein, the expression “quasi-continuous manner” refers to a manner of performing a process which may include one or more interruptions of the named process, wherein however the interruptions are distributed over the time such that a similar or a substantially same result is achieved as in a completely continuous process. For example, a quasi-continuous process may be repeatedly or regularly interrupted.

[0064] Herein, the terms “filtration” and “filtering” refer to a mechanical separation process using a filter medium that has a structure (e.g., a pore and / or mesh structure) through which particles having a size below or equal to a size defined by a structure of the medium (e.g., below a pore size of the pore structure and / or below a mesh size of the mesh structure) can pass.

[0065] The invention described herein relates to a method and an apparatus for performing a fermenting process. Optionally, the fermenting process may produce a yeast- fermented drink, e.g., beer, honey wine, and kombucha. Further optionally, the fermenting process may produce beer (e.g. bottom-cropping beer). However, the fermenting process is not limited to the production of a drink or any particular drink.

[0066] Figures 1 and 2 show flow charts for a method for performing a fermenting process in a fermentation vessel according to an embodiment, wherein FIG. 2 explains the step S3 from FIG. 1 in more detail.

[0067] The method comprises the step S1 of supplying a yeast suspension into a fermentation vessel. In step S2, during the fermentation process, the yeast suspension is fermented within the fermentation vessel. For example, wort including yeast may be fermented within the fermentation vessel during a fermentation process, but the invention may equally ferment other yeast suspensions, hence, the invention is not limited to the fermentation of wort including yeast. P93096

[0068] 10

[0069] Moreover, the method comprises step S3 of carrying out a recirculating process during at least part of the fermentation process in a continuous manner or at least in a quasi-continuous manner.

[0070] As shown in Figure 2, the recirculating process of S3 includes withdrawing yeast suspension (including accumulated yeast which is accumulated in a lower portion of the fermentation vessel during fermentation during step S2) from the lower portion of the vessel (S31 ).

[0071] The recirculating process further includes filtering the withdrawn yeast suspension by means of a filtering device to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate (S32).

[0072] The recirculating process further includes the step of recirculating the permeate into the fermentation vessel (S33).

[0073] For example, the yeast retentate from the filtering device may not be recirculated in a continuous or quasi-continuous manner into the fermenting process.

[0074] Optionally, the yeast retentate from the filtering device may be transmitted from the filtering device to a yeast collection reservoir. For example, the yeast retentate may be further packaged to be sold independently and / or the yeast in the yeast collection reservoir may be inserted at the beginning of a future fermenting process.

[0075] Optionally, the filtering device may comprise or may be a dynamic cross-flow filtration device (e.g., a dynamic cross-flow filtration device as described in EP 2 905 067 A1 ), further optionally, may be a dynamic cross-flow filtration device comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the cross-flow filtration device.

[0076] FIG. 3 shows an apparatus for performing a fermenting process according to an embodiment. Optionally, the apparatus may be configured to execute the abovedescribed method for performing a fermenting process in a fermentation vessel. P93096

[0077] 11

[0078] The apparatus comprises a fermentation vessel 10 with an upper vessel portion and a lower vessel portion, a suspension supply device 20, a recirculation line 30, and a filtering device 40 provided in the recirculation line 30.

[0079] The suspension supply device 20 is configured to supply a yeast suspension into the fermentation vessel 10. The yeast suspension supplied may optionally be a wort including yeast. For example, the suspension supply device 20 may be configured to supply the yeast suspension via the upper portion of the fermentation vessel 10.

[0080] The recirculation line 30 has one end connected to the lower portion of the fermentation vessel 10 and another end connected to a remaining portion (e.g., an upper portion) of the fermentation vessel 10.

[0081] The one end of the recirculation line 30 connected to the lower portion of the fermentation vessel 10 allows to withdraw yeast suspension including accumulated yeast (which may have been accumulated in said lower portion of the vessel 10) from said lower portion of the vessel 10.

[0082] The filtering device 40 is configured to filter the withdrawn yeast suspension from the fermentation vessel 10 so as to obtain extracted yeast as retentate and remaining liquid as permeate from the withdrawn yeast suspension.

[0083] The recirculation line 30 is configured to allow recirculation of the permeate of the filtering device 40 into the fermentation vessel 10 via the remaining portion of the fermentation vessel 10 (e.g., the upper portion of the fermentation vessel 10).

[0084] In the embodiment of FIG. 3, a retentate line 80 of the apparatus may be configured to transmit the yeast retentate from the filtering device 40 to a yeast collection reservoir 70. For example, yeast in the yeast collection reservoir 70 may be packaged to be sold independently and / or yeast in the yeast collection reservoir 70 may be inserted at the beginning of another fermenting process. P93096

[0085] 12

[0086] The filtering device 40 and the recirculation line 30 of the embodiment of FIG. 3 may be configured to prevent the retentate from being recirculated in a continuous or quasi-continuous manner into the fermenting process.

[0087] In the embodiment of FIG. 3, the fermentation vessel 10 may be a CCV. For example, the connection between the one end of the recirculation line 30 and the lower portion of the fermentation vessel 10 may be via a pre-established sample drawing line (e.g., via a commonly used sample drawing line of a CCV).

[0088] The apparatus of the embodiment of FIG. 3 may comprise a pump 50 and an electronic control device 60. The pump 50 may be provided in the recirculation line 30. The pump 50 may be configured to pump withdrawn yeast suspension from the lower portion of the vessel 10 towards and through the filtering device 40. Moreover, the pump 50 may be configured to pump the permeate from the filtering device 40 back towards and into the fermentation vessel 10 via the remaining portion of the fermentation vessel 10. The electronic control device 60 may be configured to control the operation of the apparatus in a manner such that a recirculating process is carried out via the recirculation line 30 continuously or at least quasi-continuously during at least part of the fermentation process (optionally during at least for the most part of, the fermentation process). The recirculating process controlled by the electronic control device 60 comprises withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel by means of the recirculation line 30, filtering the withdrawn yeast suspension by means of the filtering device 40 to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate, and recirculating the permeate into the fermentation vessel 10 via the remaining part of the fermentation vessel 10 by means of the recirculation line 30.

[0089] In the embodiment shown in FIG. 3, the filtering device 40 may comprise a cross-flow filtration device. In this embodiment, the filtering device 40 comprises one vertical rotary shaft that rotates around its longitudinal axis. Attached to the vertical rotary shaft of this embodiment, there are multiple horizontally aligned membrane discs that are rotated by the rotation of the vertical shaft. Said membrane discs have an inner volume, and the inner volume of said discs is fluidly connected with each other as P93096

[0090] 13 well as the other end of the recirculation line 30 connected to the upper portion of the vessel 10. In this way, the apparatus of the embodiment shown in FIG. 3 can obtain permeate in the inner volume of the membrane discs that can be recirculated into the vessel 10. Moreover, this configuration allows for the yeast retentate to be guided by the retentate line 80 to the yeast collection reservoir 70.

[0091] Optionally, the control device 60 may be further configured to control the recirculating process in such manner that the recirculating process is started after a time after the start of the fermentation process. For example, said time is predetermined or said time is determined based on at least one characteristic of the yeast suspension within the fermentation vessel 10. Optionally, said at least one characteristic of the yeast suspension may be based on a detected content of accumulated yeast in the lower portion of the vessel 10 and / or on a detected alcohol content of the yeast suspension.

[0092] The recirculation line 30, at its one end, may be directly connected to the lower portion of the fermentation vessel 10, and / or, the recirculation line 30, at its other end, may be directly connected to the remaining portion of the fermentation vessel 10.

[0093] FIG. 4 shows an apparatus for performing a fermenting process according to another embodiment. Optionally, the apparatus may be configured to execute the abovedescribed method for performing a fermenting process in a fermentation vessel.

[0094] The apparatus of the embodiment shown in FIG. 4 is similar to the one shown in FIG. 3, and only differs therefrom by the configuration of the filtering device 40’. Hence, a description of the remaining features of the apparatus is omitted.

[0095] In the embodiment shown in FIG. 4, the filtering device 40 is a dynamic cross-flow filtration device (DCF) comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the cross-flow filtration device. In this embodiment, the two rotary shafts each have multiple horizontally aligned membrane discs attached thereto. Both vertical rotary shafts may rotate along their respective longitudinal axis (and the membrane discs attached rotate accordingly due to the P93096

[0096] 14 rotation of the rotary shafts). In this embodiment, the inner volume of all the membrane discs and both rotary shafts may be fluidly connected with each other and with the other end of the recirculation line 30 connected to the upper portion of the vessel 10. In the embodiment shown in FIG. 4, the membrane discs of the two rotary shafts may be arranged in a manner in which discs of one shaft may be partly positioned in the vertical space between two discs of the other rotary shaft.

[0097] Each of the apparatuses 100 described above may be part of a brewing plant 200, as shown exemplarily in FIG. 5, and said brewing plant 200 further comprises a brew kettle 300. Said brew kettle 300 is connected to and arranged upstream from the above-described apparatus 100.

Claims

1. P9309615CLAIMS1 . Method for performing a fermenting process in a fermentation vessel, optionally by using the apparatus of any one of claims 7 to 14 or by using the brewing plant according to claim 15, comprising- supplying a yeast suspension, optionally a wort including yeast, into the fermentation vessel (S1 ),- fermenting, during the fermentation process, the yeast suspension within the fermentation vessel (S2), wherein, during the fermenting process, yeast can accumulate in a lower portion of the vessel, and- during at least part of, optionally during at least for the most part of, the fermentation process, carrying out a recirculating process in an at least quasi- continuous or continuous manner (S3), which recirculating process comprises:-- withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel (S31 ),-- separating, optionally filtering, the withdrawn yeast suspension by means of a separating device, optionally a filtering device, to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate (S32), and-- recirculating the permeate into the fermentation vessel (S33).

2. Method according to claim 1 , wherein the recirculating process is started after a time after the start of the fermentation process.

3. Method according to claim 2, wherein said time is predetermined or wherein said time is determined based on at least one characteristic of the yeast suspension within the fermentation vessel, optionally based on a detected content of accumulated yeast in the lower portion of the vessel and / or on a detected alcohol content of the yeast suspension.P93096164. Method according to any one of the preceding claims, wherein the separating device comprises a cross-flow filtration device, optionally a dynamic cross-flow filtration device.

5. Method according to any one of claims 1 to 3, wherein the separating device comprises a dynamic cross-flow filtration device comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the cross-flow filtration device.

6. Method according to any one of the preceding claims, wherein the fermentation vessel is a cylindroconical vessel.

7. Apparatus for performing a fermenting process in a fermentation vessel (10), comprising- a fermentation vessel (10) provided to have an upper vessel portion and a lower vessel portion,- a suspension supply device (20), configured to supply a yeast suspension, optionally a wort including yeast, into the fermentation vessel (10), optionally into the fermentation vessel (10) via the upper portion thereof,- a recirculation line (30)-- having one end connected to the lower portion of the fermentation vessel (10) to thereby allow to withdraw yeast suspension, including accumulated yeast which may have been accumulated in the lower portion of the vessel (10), from said lower portion of the vessel (10), and-- having another end connected to a remaining portion, optionally an upper portion, of the fermentation vessel (10), and- a separating device, optionally a filtering device, (40, 40’) provided in the recirculation line (30), which is configured to separate, optionally to filter, the withdrawn yeast suspension to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate, wherein the recirculation line (30) is configured to allow to recirculate the permeate into the fermentation vessel (10) via the remaining portion of the fermentation vessel (10).

8. Apparatus according to claim 7, further comprisingP9309617- a pump (50) provided in the recirculating line (30) and configured to pump-- the withdrawn yeast suspension from the lower portion of the vessel (10) towards and through the separating device (40, 40’), and-- the permeate from the separating device (40, 40’) back towards and into the fermentation vessel (10) via the remaining portion of the fermentation vessel (10), and- an electronic control device (60) configured to control the operation of the apparatus in a manner such that, during at least part of, optionally during at least for the most part of, the fermentation process, a recirculating process is carried out via the recirculation line (30) in an at least quasi-continuously or continuously manner, which recirculating process comprises:-- withdrawing yeast suspension, including accumulated yeast, from the lower portion of the vessel (10) by means of the recirculation line (30),-- separating, optionally filtering, the withdrawn yeast suspension by means of the separating device, optionally the filtering device, (40, 40’) to thereby obtain, from the withdrawn yeast suspension, extracted yeast as retentate and remaining liquid as permeate,-- recirculating the permeate into the fermentation vessel (10) via the remaining part of the fermentation vessel (10) by means of the recirculation line (30).

9. Apparatus according to claim 8, wherein the control device (60) is further configured to control the recirculating process in such manner that the recirculating process is started after a time after the start of the fermentation process.

10. Apparatus according to claim 9, wherein said time is predetermined or wherein said time is determined based on at least one characteristic of the yeast suspension within the fermentation vessel (10), optionally based on a detected content of accumulated yeast in the lower portion of the vessel (10) and / or on a detected alcohol content of the yeast suspension.11 . Apparatus according to any one of claims 7 to 10, wherein the separating device (40, 40’) comprises a cross-flow filtration device, optionally a dynamic crossflow filtration device.P930961812. Apparatus according to any one of claims 7 to 10, wherein the separating device (40’) comprises a dynamic cross-flow filtration device comprising at least two rotary shafts in a vertical arrangement therein with respect to a bottom of the crossflow filtration device.

13. Apparatus according to any one of claims 7 to 12, wherein the fermentation vessel (10) is a cylindroconical vessel.

14. Apparatus according to any one of claims 7 to 13, wherein the recirculation line (30), at is one end, is directly connected to the lower portion of the fermentation vessel (10) and / or wherein the recirculation line (30), at its other end, is directly connected to the remaining portion of the fermentation vessel (10).

15. Brewing plant (200) comprising a brew kettle (300) and an apparatus (100) according to any one of claims 7 to 14, wherein the apparatus (100) is connected to and arranged downstream of the brew kettle (300).

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