Inline processing of brewers' spent grains into a high fiber liquid flour

Abstract

The invention relates to a method for producing a high fiber liquid flour from brewers' spent grain, the method comprising: receiving brewers' spent grain from a brewing process preferably by a lauter tun or a mash filter; separating wort from the brewers' spent grain; receiving the brewers' spent grain at a buffer vessel, hopper or directly inline; supplying a consistent feed stream of the brewers' spent grain to a first pump; pumping the brewers' spent grain by the first pump to a second pump; shearing and grinding the brewers' spent grain by the second pump to produce a brewers' spent grain slurry with two different particle size ranges of 100-450 μm and 450-850 μm, wherein the brewers' spent grain slurry in these two particle size ranges is the high fiber liquid flour.

Description

[0001] INLINE PROCESSING OF BREWERS’ SPENT GRAINS INTO A HIGH FIBER LIQUID FLOUR

[0002] Field

[0003] The present disclosure relates to the processing of brewers’ spent grains and to a respective system. More specifically, the present disclosure relates to inline processing of brewers’ spent grains to produce a high fiber liquid flour which may be used to at least partly substitute for conventional flour in the processing of dough.

[0004] Background

[0005] Brewers’ spent grain (BSG) is a byproduct generated in the beer production process, arising from the residual grains after mashing and lautering. Typically composed of malted barley, wheat, rye or corn, BSG contains husks, protein, and fiber. In large- scale brewing operations, significant quantities of brewers’ spent grain are produced, posing both a challenge in waste management and an opportunity for sustainable resource utilization.

[0006] Traditionally considered a byproduct with limited applications, BSG has found valuable use as an animal feed ingredient due to its residual nutritional content, including protein and high fiber content. Collaboration between breweries and local farmers has emerged as a common practice, facilitating the repurposing of spent grain as a cost- effective feed source for livestock.

[0007] However, urban breweries, in particular, encounter difficulties regarding the disposal of brewers' spent grain (BSG) and waste management, as farmers are frequently unavailable in these areas. Consequently, the disposal of BSG becomes an added expense for urban breweries. As a result, a prevalent alternative disposal method involves utilizing BSG for biogas production. Yet, the sustainability of this method is uncertain due to its potential for increased greenhouse gas emissions.

[0008] Despite its established use as animal feed and the production of biogas, there remains a need for innovative approaches to maximize the utility of BSG, both in enhancing its nutritional value and exploring alternative applications beyond traditional livestock feed.

[0009] Summary

[0010] An aspect of the present disclosure provides a novel method for processing brewers’ spent grain (BSG). The method includes an inline process to convert the BSG into a BSG- slurry using a specific pump solution and arrangement. The produced BSG- slurry can then be used in bakeries and other dough processing companies to partly substitute conventional flour.

[0011] An embodiment of the present disclosure provides a method for producing a high fiber liquid flour from brewers’ spent grain. The method includes receiving brewers’ spent grain from a brewing process at a lauter tun, mash filter or any other equipment, which is separating wort from the brewers’ spent grain, and receiving the wort removed brewers’ spent grain at a buffer vessel, hopper or directly in-line. The method further includes supplying a feed stream of the brewers’ spent grain to a first pump, pumping the brewers’ spent grain by the first pump to a second pump, and shearing and mixing the brewers’ spent grain by the second pump to produce a brewers’ spent grain slurry with two different particle size ranges of 100-450 pm and 450-850 pm. The brewers’ spent grain slurry in these two-particle size ranges is the high fiber liquid flour.

[0012] In some examples, the shearing and mixing the brewers’ spent grain by the second pump produces a brewers’ spent grain slurry having a continuous particle size distribution extending through two different particle size ranges of 100-450 pm and 450-850 pm.

[0013] As used herein, the term "continuous particle size distribution extending through two different particle size ranges" refers to a single distribution that contains particles within both the 100-450 pm range and the 450-850 pm range. The distribution is 'continuous' in that it represents a single population of particles produced in one grinding process, rather than two separate batches mixed together. Particles are distributed across both ranges, though not necessarily in equal proportions, it would also be understood by a person skilled in the art, that the population may also contain some particles outside of these ranges.

[0014] The spent grain slurry with the smaller particle size is a medium spent grain slurry, while the spent grain slurry with the larger particle size is a coarse spent grain slurry.

[0015] The grinding of the brewers’ spent grain is needed to reduce the particle sizes from the brewers spent grain to be comparable to conventional wheat flour which ranges from 50 pm to 200 pm. In addition, the grinding process-based reduction in particle sizes might result in following benefits for further processing, especially in the industrial baking process. The tested particle size range of 100-450 pm is small enough to integrate smoothly into the dough, improving the overall texture of the baked goods. It may also help to achieve a finer crumb structure, enhance mouthfeel while simultaneously preventing the product from becoming dense. This particle range also ensures that the fiber is evenly distributed throughout the dough, increasing the dietary fiber content without compromising the quality of the final product. Based on the increase of surface area in relation to its volume, the ground brewers spent grain shows increased water absorption properties then untreated brewers spent grain. Dough produced using high fiber liquid flour in the range of 100-450 pm also shows improved dough elasticity and handling properties. This is facilitating the baking process and provides an advantage in automated baking environments where consistency is crucial. The coarse spent grain slurry with a particle range of 450-850 pm can provide additional structural integrity to baked goods. It can be utilized as a filler, reducing shrinkage during baking helping maintain the shape and size of the final product. These larger particles can create a coarser, more rustic texture in the finished product, which can be desirable in certain types of bread and baked goods as well as add a pleasant crunch or chewiness, enhancing the sensory experience. The spent grain slurry with the particle size range of 450-850 pm can be used to prevent the final product from becoming dry too quickly by its gradual water release capabilities compared to conventional flour. Larger particles release water more slowly compared to finer particles, which can help in maintaining moisture over a longer period. Using a mix of both particle size ranges (100-450 pm and 450-850 pm) can combine the advantages of both, leading to optimal texture, improved dough properties and extended shelf life.

[0016] These benefits have been validated in lab scale as well in industrial small scale through our industrial partners.

[0017] The particle sizes are measured using a Laser Diffraction or Laser Scattering method. For these analytical devices that have been used, the conduct methods are based on the DIN standard for laser diffraction or scattering for particle size analysis (DIN ISO 13320). More precisely DIN ISO 13320:2020-09. This standard ensures that the laser diffraction method is applied consistently and reliably, serving as an important reference for particle size analysis in research and industry.

[0018] In some aspects, the second pump is a shear or dispersion pump. This pump type is primarily used for comminution and homogenization of mixtures based on a liquid and solid components; these pump types can also be considered a rotary homogenizer. This rotary homogenizer differs from pumps commonly used in the brewing industry by its characteristic capability to produce high shear forces. The used model for industrial application might be a FSP 3532 / 175 VD form the company Fristam Pumpen KG. The second pump can also be a colloid mill. This colloid mill is also installed inline to grind the brewers spent grain to its desired particle sizes. The used model for industrial application might be a colloid mill Packo Series CM from Verder Deutschland GmbH & Co. KG. The first pump can be understood as a BSG supply pump since it will transport the BSG towards the second pump.

[0019] The first pump can be an eccentric screw pump. The first pump can be a hopper pump. The first pump can be a Twin Screw Pump. The first pump is characterized by its low shear forces and its reduced risk to damage or pre grind the brewers spent grain before the second pump. Its task is to transport the high moisture BSG towards the second pump and produce the defined inlet pressure needed by the second pump. The first pump may be specified based on a water content of BSG coming from lauter tun. A normal water content of BSG may be between 70% and 85%. Water may be optionally added if needed, to increase a processability of BSG from lauter tun. Water might be added in the lauter tun when removing BSG and / or may be added inline to support flow if needed. A particle size of BSG may vary per brewery based on how the brewing malt has been treated before mashing in. The BSG Feed Pump might be a NEMO B.Max mixing pump from Erich NETZSCH B.V. & Co. Holding KG or a Mono WIDETHROAT pump from AxFIow GmbH.

[0020] BSG may be taken directly from the lauter tun as soon as the coordinated sub-steps in the brewing process allow it to keep a temperature of BSG as high as possible. Normally BSG temperature may range between 70 °C - 80 °C when coming directly from the lauter tun. A process temperature (end-to-end) may not be lower < 60 °C to ensure micro-biological stability.

[0021] While the first pump pumps BSG to the second pump, the second pump grinds the BSG to produce BSG slurry. BSG slurry may be a high fiber liquid flour which may be suitable for substituting into conventional flour up to about 30% by mass. For this purpose, the second pump may include a toothed rotor-stator combination seen in the Fristam FSP 3532 / 175 VD pump, or the Packo Series CM, which can process a wide variety of material such as BSG. The second pump may include a variable speed drive which may allow the pump to adjust a shear and mixing effect when processing BSG into BSG slurry. The second pump may texturize BSG to give a smooth body and texture to BSG slurry.

[0022] Adjustments made to the second pump may adjust a final distribution of particle sizes produced for BSG slurry. Particle size in BSG slurry may be adjusted by changing a rotor of the second pump, as well as using different rotor-stator ratios with different number of teeth and varying gap sizes. When using the rotary homogenizer or colloidal pump, the amount of grinding teeth at the rotor and stator can be increased, to increase the surface area for shearing and grinding. Hereby each pass through the rotor-stator assembly subjects the product to more frequent shearing actions, which contributes to further particle size reduction. More grinding teeth lead to a more uniform particle size. If the rotor-stator assembly originally has 20 teeth, increasing it to 40 teeth will double the shearing actions per rotation, improving the particle size reduction efficiency. The second parameter that directly influences the particle size is the distance between the rotor and stator. By reducing the distance between the stator and the rotor of the rotary homogenizer, the shear forces acting on the particles are increased because the product is forced through a narrower gap, causing higher velocity gradients and more intense shear forces. The reduction of the distance between stator and rotor when using a colloidal mill also results in the desired reduction of particle sizes. This is achieved by adjusting the annular gap between stator and rotor. This annular gap can be adjusted by changing the axial position of the rotor.

[0023] The particle sizes of the produced high fiber liquid flow can also be adjusted, by regulating the speed the second pump is operated at. Increasing the speed of the second pump or colloidal mill raises the shear forces applied to the particles. This higher shear rate enhances the breakdown of larger particles into smaller ones, leading to a finer particle size distribution. However, very high speeds can sometimes reduce the residence time of particles in the shear zone, potentially leading to less uniform particle size reduction. In addition, the speed of the second pump needs to be in alignment with the first pump and the defined brewing steps in the brewery to ensure a constant supply of brewers spent grain from the brewhouse.

[0024] Therefore, a combination of different rotor-stator grinding teeth ratios in combination with an adjustment of the distance between stator and rotor, plus an adjustment of the pump speed is needed to produce the right ranges in particle size.

[0025] The system may be configured to perform a subsequent shearing and grinding step, following the first shearing a grinding with a second pump, such as for example, recirculating the BSG through the same second pump, processing BSG through two sequential pumps, or processing through a dispersion pump followed by processing through a colloidal mill.

[0026] The processing system produces brewers' spent grain slurry characterized by having particles distributed across two different particle size ranges of 100-450 pm and 450- 850 pm.

[0027] The relative proportions of particles in each size range can be influenced through processing parameters, such as pump speed, rotor-stator gap, number of grinding teeth, and processing configuration, to optimize the product for specific applications. While the slurry contains particles across multiple size ranges, the processing can be tuned to favor either finer particle distributions (with more particles in the 100-450 pm range) or coarser particle distributions (with more particles in the 450-850 pm range).

[0028] A single dispersion pump configuration produces BSG slurry with modal particle sizes in the 450-850 pm range, creating a coarse liquid flour suitable for structural applications. Sequential processing through a dispersion pump followed by a colloid mill produces a BSG slurry with modal particle sizes in the 100-450 pm range, creating a medium liquid flour suitable for smooth texture applications. The resulting slurries maintain heterogeneous particle distributions while achieving controlled modal targeting for specific functional requirements.

[0029] By adjusting the processing parameters such as pump speed, rotor-stator gap, number of grinding teeth, and processing configuration, BSG slurry may be produced in two particle size categories; a medium BSG slurry which may have particles of about 100 - 450 pm with a mass percentage (%) of greater than 80, and a coarse BSG slurry which may have particles of about 450 - 850 pm with a mass percentage (%) of greater than 80.

[0030] BSG slurry may be optionally further processed. A heat exchanger, a pressor or centrifuge and packaging station might be present. The heat exchanger may heat the BSG up to a temperature of > 85 °C for a minimum of 20 seconds. The temperature of the BSG might not fall below 65 °C until packaged. This may stabilize BSG slurry. The pressor or centrifuge may be a belt or screw press or a centrifuge or decanter and may dewater the BSG slurry up to a moisture content of about 40%. The BSG is dewatered to increase stability, value and reduce costs for logistics. At the packaging station, BSG slurry may be packaged into totes, drums or any other packaging suitable for storage of BSG slurry.

[0031] Another embodiment of the present disclosure provides high fiber liquid flour made by the process of receiving brewers’ spent grain from a brewing process at a lauter tun, separating, by the lauter tun, wort from the brewers’ spent grain, and receiving the wort removed brewers’ spent grain at a buffer vessel or hopper. The process further includes supplying a consistent feed stream of the wort removed brewers’ spent grain to a first pump, pumping the wort removed brewers’ spent grain by the first pump to a second pump, and shearing and mixing the wort removed brewers’ spent grain by the second pump to produce a brewers’ spent grain slurry with a homogeneous particle size. The brewers’ spent grain slurry with homogeneous particle size is the high fiber liquid flour.

[0032] In some aspects, a food product is made from the high fiber liquid flour.

[0033] In a further aspect, the invention concerns a system, in other words a process unit for producing a high fiber liquid flour from brewers’ spent grain which comprises a buffer vessel or a hopper which is configured to receive brewers’ spent grain. The buffer vessel or the hopper can be made of stainless steel, black steel or plastic.

[0034] The system processes brewers spent grain provided by a lauter tun, mash filter or any other equipment, which is separating wort from the brewers’ spent grain.

[0035] The system has a first pump and a second pump. The first pump is configured to receive a feed stream of the brewers’ spent grain and to feed the brewers’ spent grain by the first pump to a second pump, wherein the second pump is configured to shear the brewers’ spent grain to produce a brewers’ spent grain slurry with two different particle size ranges. The brewers’ spent grain slurry with its two different particle size ranges is the produced high fiber liquid flour. In particular, the system is configured to produce a high fiber liquid flour described above and / or conduct a method described above.

[0036] The brewers’ spent grain could also be fed directly to the first pump, using piping or hoses, preferably made of different materials. The buffer vessel or the hopper might have a spray ball installed to rinse it after use and to increase the water ratio in the brewers’ spent grain if needed.

[0037] Between the first pump and the second pump an additional connection pipe might be installed which reduces the occurrence of turbulence before the second pump. This connection might include a connection point for brewers’ spent grain sampling as well as allows the backflushing of the pipes if needed. The diameter of the installed connection might differ.

[0038] In some configurations the system may have a third pump downstream of a second pump. The third pump may be a dispersion pump. The third pump may be a colloidal mill.

[0039] The system is configured to be mobile. The system can be mounted on a frame which might be manufactured of stainless steel, black steel or any other suitable material. The frame can have a minimum of three wheels mounted to make the unit mobile.

[0040] An electrical cabinet might be mounted to the frame which might be used for individual speed control of both pumps.

[0041] The system might further have a heat exchanger, a pressor or centrifuge and packaging station might be present. The heat exchanger may provide heat to BSG slurry which may stabilize BSG slurry. The pressor or centrifuge may be a belt or screw press or a centrifuge and may dewater BSG slurry. At the packaging station, BSG slurry may be packaged into totes, drums or any other packaging suitable for storage of BSG slurry.

[0042] Further details and aspects of the present disclosure are described in more detail below with reference to the appended figures:

[0043] Brief Description of the Drawings

[0044] A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative aspects, in which the principles of the present disclosure are utilized, and the accompanying figure of which:

[0045] Fig. 1 illustrates an embodiment of a system to convert brewers' spent grain (BSG) into a BSG-slurry that can then be used as a partial substitute for conventional flour, in accordance with aspects of the present disclosure. Fig. 2 depicts another embodiment of the system to convert BSG into BGS-slurry.

[0046] Fig. 3 depicts a perspective view of the system to convert BSG into BGS-slurry according to some examples.

[0047] Fig. 4 shows a side of the system as shown in Fig. 3.

[0048] Fig. 5 shows a schematic view of the system to convert BSG into BGS-slurry together with additional optional post processing components.

[0049] Fig. 6 shows particle size frequency distributions for brewers' spent grain slurry samples A, B, and C.

[0050] Detailed Description

[0051] The present disclosure relates to a system to convert brewers' spent grain (BSG) into a BSG-slurry that can then be used as a partial substitute for conventional flour. Aspects of the present disclosure are described in detail with reference to the figure wherein like reference numerals identify similar or identical elements.

[0052] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to exemplary aspects illustrated in the figure, and specific language will be used to describe the same.

[0053] Figure 1 illustrates a system 100 to convert brewers’ spent grain (BSG) into a BSG- slurry that can then be used as a partial substitute for conventional flour, arranged in accordance with at least some embodiments described herein. System 100 may include a lauter tun 10, a buffer vessel / hopper 20, a first pump 30, and a second pump 40. BSG 50 from a brewing process may be incurred at the lauter tun 10. The lauter tun 10 may create brewers’ spent grain (BSG) 55 as a result of the brewing process by separating wort from solid components. Brewers Mash 50 is fed to the lauter tun, after the removal of the liquid fraction (wort) the remaining solids is BSG 55. As understood by those skilled in the art, BSG 55 represents the solid fraction of the mashing process, distinguished from the liquid wort, though it retains substantial moisture content. Typically, BSG 55 as discharged from the lauter tun 10 has a water content between 70% and 85% by weight, resulting in a flowable, paste-like consistency suitable for pumping operations. This moisture content is characteristic of standard brewing operations and enables the subsequent inline processing described herein. The lauter tun 10 may supply BSG 55 to buffer vessel / hopper 20. Buffer vessel / hopper 20 may buffer an irregular stream of BSG 55 coming from lauter tun 10 and create a consistent feed stream of BSG 55 to an inlet of the first pump 30. The first pump 30 may be a hopper pump or may be a screw pump feeding the second pump 40 which might be a disperser pump or colloidal mill. The first pump 30 may be specified based on a water content of BSG 55 coming from lauter tun 10.

[0054] Figure 2 illustrates a system 100 to convert brewers’ spent grain (BSG) into a BSG- slurry that can then be used as a partial substitute for conventional flour, arranged in accordance with at least some embodiments described herein. System 100 may include a buffer vessel / hopper 20, a first pump 30 depicted as a screw pump, and a second pump 40.

[0055] In addition, Figure 2 shows a spray ball 21 for CIP. The system 100 comprises a frame 22. The frame 22 provides the structure for mounting the components of the system 100. The frame 22 is optionally made from 304 stainless steel. In addition, wheels 23 are mounted to the frame 22. As shown in Figure 4, the wheels 23 may be castors and allow the frame 22 to be pushed in different directions more easily. This means that the system 100 is deployable in different positions within a production line. The system 100 is connected to a control cabinet 24 which houses a controller. A user can control one or more operations of the system from the control cabinet 24. Figure 2 further shows an optional T-piece 31 in fluid communication with the first pump 30 and the second pump 40. The T-piece is arranged to add water to the flush one or more pipes of the system 100 and similarly drain water from one or more pipes from the system 100.

[0056] In some examples, the system 100 is mounted on a moveable frame 22. This means that the hopper 20, the first pump 30 and the second pump 40 are mounted to the same frame 22. Accordingly, all the components of the system 100 can be moved in unison. This makes installation and retrofitting of the system 100 to existing production lines easier. Furthermore optionally the frame 22 comprises guide tubes 150 arranged to receive the forks of a fork lift truck. This means that the system 100 can be more easily loaded and unloaded from a heavy goods vehicle. In some examples, the guide tubes 150 are positioned on the underside of the frame 22 and positioned underneath a centre of mass of the components of the system 100 mounted to the frame 22. In some examples, the frame comprises a housing (not shown) which encloses the first pump 30 and the second pump 40.

[0057] A normal water content of BSG 55 may be between 70% and 85%. Water may be optionally added if needed, to increase a processability of BSG 55 from lauter tun 10. Water might be added in lauter tun 10 when removing BSG 55 or may be added inline to support flow if needed. A particle size of BSG 55 may vary per brewery based on how the brewing malt has been treated before mashing in. A difference in particle size of BSG 55 may, for example, be related to brewing equipment that has been used to crush the malt (i.e. hammer vs. roller mill). In general, Table 1 presents a distribution of particle sizes of brewers’ spent grain BSG 55.

[0058] Table 1 .

[0059] BSG 55 may be taken directly from the lauter tun 10 as soon as the coordinated substeps in the brewing process allow it to keep a temperature of BSG 55 as high as possible. Normally BSG 55 temperature may range between 70C° - 80C° when coming directly from the lauter tun 10. A process temperature (end-to-end) may not be lower < 60C° to ensure micro-biological stability.

[0060] The first pump 30 may pump BSG 55 and feed BSG 55 to the second pump 40. The second pump 40 may perform a second pumping step and may grind the BSG 55 while pumping BSG 55 to produce BSG slurry 60. BSG slurry 60 may be a high fiber liquid flour which may be suitable for substituting into conventional flour up to about 30% by mass.

[0061] The second pump 40 may include stators and rotors which can process a wide variety of material such as BSG 55. The second pump 40 might be a colloidal mill. The second pump 40 may include a variable speed drive which may allow the second pump 40 to adjust a shear and mixing effect when processing BSG 55 into BSG slurry 60. The second pump 40 may texturize BSG 55 to BSG slurry 60. The BSG slurry typically has a moisture content of at least 65% by weight, preferably at least 70% by weight, such as between 70% and 85% by weight.

[0062] As used herein, the 'second pump' may be understood as an individual pump or as a pump system that can comprise a single pump or multiple pumps, such as two pumps, arranged to perform the shearing and grinding function. Optionally in some examples, the term 'second pump' may comprise second pump 40 and third pump 120, as depicted in Figure 3 - Figure 5. Optionally in some examples, the second pump may be a pump system comprising two sequential dispersion pumps, or a pump system comprising a dispersion pump followed by a colloidal mill, or a single pump with recirculation capability. In some implementations, the second pump may comprise a dispersion pump. In some implementations, the second pump may comprise a colloidal mill. The pump system is configured to receive the brewers' spent grain from the first pump and perform the shearing and grinding to achieve the desired particle size distribution.

[0063] The processing system produces brewers' spent grain slurry characterized by having particles distributed across two different particle size ranges of 100-450 pm and 450- 850 pm. The resulting slurry is a heterogeneous mixture that naturally contains particles in both size ranges due to the mechanical grinding process. The slurry may also contain a small fraction of particles outside these ranges, such as particles smaller than 100 pm and particles larger than 850 pm.

[0064] The particle size distribution can also be characterized by median particle size (Dx50), which indicates the particle size at which 50% by volume of the particles are smaller and 50% by volume are larger. The processing parameters can be adjusted to produce slurries with different median particle sizes and particle size profiles to optimize performance for specific baking applications.

[0065] The particle size distribution may take various forms while maintaining continuity through both ranges. In some embodiments, the distribution is unimodal with a single modal particle size that may be located within the 100-450 pm range, within the 450- 850 pm range, or at a size between these ranges. In other embodiments, the distribution is bimodal, exhibiting two distinct peaks. A bimodal distribution may manifest with both peaks within the 100-450 pm range, both peaks within the 450-850 pm range, or with one peak in each range.

[0066] In some implementations, the processing can produce slurries that are either predominantly fine or predominantly coarse. In some implementations, the processing can produce slurries that are either substantially fine or substantially coarse.

[0067] As used herein, "predominantly" means that greater than 50% by mass of the particles fall within the specified particle size range

[0068] As used herein, "substantially " means that greater than 80% by mass of the particles fall within the specified particle size range

[0069] As used herein, "median particle size" or "Dx50" refers to the particle size at which 50% by volume of the particles are smaller and 50% by volume are larger, as determined by laser diffraction analysis. This measurement provides a representative value for the central tendency of the particle size distribution. As used herein, the term "modal particle size" refers to the most frequently occurring particle size in a distribution, representing the peak of the particle size distribution curve as determined by particle size analysis.

[0070] As used herein, the term "bimodal particle size distribution" refers to a distribution having two peaks or maxima, which may occur within the same size range or in different size ranges, and which may manifest as two separate peaks or as a primary peak with a distinct shoulder, as illustrated in Figure 6.

[0071] Adjustments made to the second pump 40 may adjust a final distribution of particle sizes produced for BSG slurry 60. Particle size in BSG slurry 60 may be adjusted by changing a rotor of the second pump 40, as well as using different rotor-stator ratios with different number of teeth and varying gap sizes. The second pump 40 may homogenize a particle size of the resulting BSG slurry 60. In some implementations, BSG slurry 60 may be produced in one of two particle size categories; a medium BSG slurry 60 which may have particles of about 100-450 pm with a mass percentage (%) of greater than 80, and a coarse BSG slurry 60 which may have particles of about 450- 850 pm with a mass percentage (%) of greater than 80, as presented in Table 2.

[0072] Table 2.

[0073] In some implementations, the system may be configured to perform single dispersion processing, wherein the brewers' spent grain is processed through a single dispersion pump after being fed by the first pump. This configuration results in a final product with median particle size in the range of 450-850 pm.

[0074] In some implementations, the system may be configured to perform two sequential dispersion processes to achieve enhanced particle size reduction. This can be achieved either by creating a recirculation loop where the BSG passes through the same dispersion pump twice, or by employing two dispersion pumps arranged in series. The first dispersion pump performs an initial grinding step, and the second dispersion pump performs additional particle size reduction. This configuration produces a product with median particle size in the range of 100-450 pm or in the range of 450-850 pm, while maintaining the benefit of using only dispersion pump technology, thereby avoiding the higher capital expenditure and operational complexity associated with colloidal mills.

[0075] The system may be configured to perform combined dispersion-colloidal processing, wherein the BSG first passes through a dispersion pump for initial grinding, followed immediately by processing through a colloidal mill for final particle size reduction. The dispersion pump performs the initial coarse grinding, and the colloidal mill provides the fine grinding to achieve a product with median particle size in the range of 100-450 pm.

[0076] The introduction of a subsequent shearing and grinding step, such as recirculating the BSG through the same second pump 40, processing BSG through two sequential pumps 40, may produce a product with median particle sizes (Dx50) typically in the range of approximately 150-350 pm, such as approximately 150-200 pm.

[0077] The particle size distribution may take various forms while maintaining continuity through both ranges. In some embodiments, the distribution is unimodal with a single modal particle size that may be located within the 100-450 pm range, within the 450- 850 pm range, or at a size between these ranges. In other embodiments, the distribution is bimodal, exhibiting two peaks. A bimodal distribution may manifest with both peaks within the 100-450 pm range, both peaks within the 450-850 pm range, or with one peak in each range.

[0078] BSG slurry 60 may be optionally further processed. System 100 may optionally include a heat exchanger 70, a pressor or centrifuge 80, and packaging station 90. Heat exchanger 70 may provide heat 71 to BSG slurry 60 which may stabilize BSG slurry 60. Water 61 can be added. Recovered warm water 62 might be returned to the vessel / buffer 20. The pressor or centrifuge 80 may be a belt or screw press or a centrifuge and may dewater BSG slurry 60 such that water 61 is removed. At packaging station 90, BSG slurry 60 may be packaged into totes, drums or any other packaging suitable for storage of BSG slurry 60. Also, in this step, heat 71 might be applied.

[0079] A process according to the present invention may provide a method of processing brewers’ spent grain. A process according to the present invention may provide a method to convert regular brewers’ spent grain into a BSG-slurry that can be reintroduced back into the food production chain by substituting conventional flour up to 30%.

[0080] A process according to the present invention may provide a method which addresses the need of the brewing industry for a simple solution to process brewers’ spent grain and reduce the amount of organic waste produced during the brewing process. A process according to the present invention may provide a simple, cost effective, sustainable method to produce a BSG-slurry for food production over other available machines and processes which may be complex, cost intensive and often not sustainable.

[0081] A process according to the present invention may provide a method which utilizes an inline grinding process of brewers’ spent grain using a dispersal pump to produce a BSG- slurry in two particle sizes (medium and coarse). A process according to the present invention may provide a method which produces a BSG slurry with particle sizes that has improved processing properties for the industrial baking industry.

[0082] A process according to the present invention may provide a method which provides a direct reintroduction of brewers’ spent grain back into the food industry production chain as a high protein and high fiber bulking material for dough producing companies. A process according to the present invention may provide a method which provides a raw material to the food industry to cut costs in production and simultaneously reduce the production of greenhouse gases and produce more sustainable products.

[0083] Figures 3 to 5 show some other examples of the system 100. Specifically Figures 3 and 4 respectively show a perspective view and a side view of the system 100. Figure 5 shows a schematic view of the system 100 connected to additional optional post processing elements. Figure 5 is similar to the arrangement as shown in Figure 1 , except that there are additional pumps.

[0084] The elements as shown in Figure 5 in the dotted box labelled 100 are the elements as previously described and function in the same way.

[0085] The hopper 20 may be optionally in fluid communication with a first pump 30. The first pump 30 is connected downstream of the hopper 20 and upstream of the second pump 40. The first pump 30 is a hopper pump and configured to pump the brewers spent grain (BSG) to the second pump 40. The first pump 30 is optional, for example the brewers spent grain (BSG) can be fed to the second pump 40 from the hopper 20 under gravity alone.

[0086] It should be noted that the second pump 40 and the third pump 120 as shown in Figure 5 can, in some examples, respectively be a disperser pump and a colloidal mill. In some other examples, the second pump 40 and the third pump 120 can be both a disperser pump. Both the second pump 40 and the third pump 120 as discussed above are configured to apply a shearing force on the brewers spent grain (BSG) in order to grind the brewers spent grain (BSG).

[0087] Optionally, the output BSG-slurry from the third pump 120 can be recirculated to the second pump 40. This may be achieved with a recirculation pipe 140 and recirculation valve. This may be desirable if the BSG-slurry requires further grinding. In some implementations, the output BSG-slurry may instead be recirculated within the second pump 40 for multiple sequential rounds of shearing / grinding.

[0088] In addition the system 100 comprises a fourth pump 110 which is connected downstream of the second pump 40 (or third pump 120 if present). The fourth pump 110 is a booster pump and arranged to pump the BSG-slurry away from the second pump 40 (or third pump 120 if present). In some examples the fourth pump 110 is a twin screw pump, but the fourth pump 110 can be any suitable pump. The fourth pump 110 is optional and may not be needed if there is sufficient pressure on the BSG-slurry when output from the second pump 40. Similar to the arrangement as shown in Figure 1, a heat exchanger 70 may be provided. The heat exchanger 70 is connected downstream of the fourth pump 110. The heat exchanger 70 is optional and not needed.

[0089] Optionally in some examples, a culture vessel 130 may be connected downstream of the heat exchanger 70. The culture vessel 130 is arranged to supply an amount of bacteria e.g. Lactobacillus. This can treat the BSG-slurry such that it is prepared for certain use cases. In one such use case, the culture vessel 130 supplies the BSG- slurry with Lactobacillus from a sour dough culture to create a sour dough from the BSG-slurry. The culture vessel 130 is optional, and may be desired only when sour dough is required.

[0090] Optionally a moisture reduction unit 80 is connected downstream of the culture vessel 130. The moisture reduction unit 80 is configured to remove water from the BSG- slurry. In some examples, the moisture reduction unit 80 is a centrifuge or a press. Alternatively, the moisture reduction unit 80 can be a non-mechanical device such as a heater or dryer.

[0091] Optionally a packaging station 90 is connected downstream of the moisture reduction unit 80. The packaging station is 90 is the same as previously described. The packaging station 90 may not be necessary because the BSG-slurry output from the moisture reduction unit 80 or any other component can be used directly. Alternatively, depending on its moisture content and physical parameters, the BSG slurry may be stored in bulk containers such as silos or tanks and then transported via food-grade tanker trucks to end users, eliminating the need for individual packaging.

[0092] Table 3 presents particle size distribution data for brewers' spent grain slurry samples produced using various pump configurations. All samples were produced from wet brewers' spent grain (70-85% moisture content) processed through different combinations of dispersion pumps and colloid mills. All samples were subjected to laser diffraction analysis according to DIN ISO 13320:2020-09, which provides a standardized and reproducible method for particle size determination. The samples were produced using the following configurations, with a dispersion pump (where applicable) operating at 5000 rpm. The gap refers to the gap setting of the colloidal mill.

[0093] Sample 1 : Dispersion pump followed by colloidal mill (0,15 mm gap).

[0094] Sample 2: Dispersion pump only.

[0095] Sample 5: Dispersion pump followed by colloidal mill (0,3 mm gap).

[0096] Sample 8: Dispersion pump only.

[0097] Sample A: Dispersion pump twice.

[0098] Sample B: Dispersion pump followed by colloidal mill (0,15 mm gap).

[0099] Sample C: Colloid mill only (0.3 mm gap).

[0100] The throughput rates of the first pump (eg. eccentric screw pump or progressive cavity pump), which refers to the delivery rate of the first pump, varied between trials and depending on the pump used. In some instances, the throughput rates of 500 to 2000 kg / h were used, such as 650 to 1800 kg / h, such as 680 kg / h, such as 1000 kg / h, such as 1300 kg / h, and such as 1600 kg / h. In some instances, the throughput rates of 100- 500 rpm were used, such as 160 rpm, such as 400 rpm. The feed rate affected residence time in the grinding equipment but did not significantly influence the final particle size distribution.

[0101] Samples A, B, and C were sieved at 1000 pm prior to analysis to remove outlier particles for analytical purposes. This sieving does not affect the particle size distribution within the claimed ranges.

[0102] The resulting slurries maintained moisture contents of 70-85% by weight.

[0103] Table 3.

[0104] It was also observed during trials that the shearing and grinding action of the second pump, particularly when configured as a combined disperser and colloidal mill, imparts significant mechanical energy into the slurry. This action results in a notable increase in the slurry's temperature, independent of external heat sources. During trials, a temperature increase of approximately 15°C to 30°C was observed. The effect was more prominent in a combined set-up of disperser pump and colloidal mill. This effect is influenced by the residence time of the slurry within the pump system, with lower flow rates leading to a greater temperature increase. This inherent heating process assists in achieving the required temperature for microbiological stabilization, thereby enhancing process efficiency and potentially reducing the energy requirements of the optional downstream heat exchanger. Optionally in some examples, the step of shearing and grinding the brewers’ spent grain concurrently heats the brewers’ spent grain slurry by at least 15°C due to mechanical shear forces. Optionally in some examples, the second pump is configured to increase the temperature of the brewers' spent grain slurry by at least 15°C through mechanical action during operation.

[0105] Figure 6 further shows particle size frequency distributions for brewers' spent grain slurry samples A, B, and C. The x-axis represents particle size in micrometers (pm) on a logarithmic scale from 0.1 to 10,000 pm. The y-axis represents volume fraction in percent (%). Sample A exhibits a bimodal distribution with a first maximum in the range of 20-80 pm and a second maximum in the range of 300-1000 pm. Sample B and Sample C show unimodal distributions with significant slope changes in the 20-80 pm range but without forming distinct secondary maxima. All three samples demonstrate continuous particle size distributions extending through both the 100-450 pm and 450- 850 pm ranges.

[0106] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0107] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0108] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0109] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

Claims1. A method for producing a high fiber liquid flour from brewers’ spent grain, the method comprising: receiving brewers’ spent grain from a brewing process preferably by a lauter tun or a mash filter; separating wort from the wet brewers’ spent grain; receiving the wet brewers’ spent grain at a buffer vessel, hopper or directly inline; supplying a consistent feed stream of the wet brewers’ spent grain to a first pump; pumping the wet brewers’ spent grain by the first pump to a second pump; shearing and grinding the wet brewers’ spent grain by the second pump to produce a brewers’ spent grain slurry having a continuous particle size distribution extending through two different particle size ranges of 100-450 pm and 450-850 pm, wherein the brewers’ spent grain slurry in these two particle size ranges is the high fiber liquid flour.

2. The method of one of claiml , where in the second pump is a dispersion pump or colloidal mill.

3. The method according to any one of claims 1 to 2, wherein the wet brewers’ spent grain has a moisture content of between 70% and 85% by weight.

4. The method according to any one of claims 1 to 3, wherein the wet brewers’ spent grain is maintained at the temperature of at least 60°C.

5. The method according to any one of claims 1 to 4, wherein the brewers’ spent grain slurry has a bimodal particle size distribution.

6. The method according to any one of claims 1 to 5, wherein the brewers’ spent grain slurry has a modal particle size within the 100-450 pm range.

7. The method according to any one of claims 1 to 5, wherein the brewers’ spent grain slurry has a modal particle size within the 450-850 pm range.

8. The method according to any one of claims 1 to 7, wherein the brewers’ spent grain slurry with particle size range of 100-450 pm has the mass percentage (%) of greater than 50 of the total brewers’ spent grain slurry, such as the mass percentage (%) of greater than 80 of the total brewers’ spent grain slurry.

9. The method according to any one of claims 1 to 7, wherein the brewers’ spent grain slurry with particle size range of 450-850 pm has the mass percentage (%) of greater than 50 of the total brewers’ spent grain slurry, such as the mass percentage (%) of greater than 80 of the total brewers’ spent grain slurry.

10. The method according to any one of claims 1 to 9, wherein the shearing and grinding the wet brewers’ spent grain step further comprises recirculating the brewers’ spent grain through the second pump.

11. The method according to any one of claims 1 to 9, wherein the shearing and grinding the wet brewers’ spent grain step comprises processing the brewers’ spent grain through two sequential dispersion pumps.

12. The method according to any one of claims 1 to 9, wherein the shearing and grinding the wet brewers’ spent grain step comprises processing the brewers’ spent grain through a dispersion pump followed by a colloidal mill.

13. A high fiber liquid flour made by the process comprising: receiving brewers’ spent grain from a brewing process, preferably by a lauter tun or a mash filter; separating wort from the wet brewers’ spent grain; receiving the wet brewers’ spent grain at a buffer vessel or hopper, or directly inline; supplying a consistent feed stream of the brewers’ spent grain to a first pump; pumping the brewers’ spent grain by the first pump to a second pump; shearing and grinding the brewers’ spent grain by the second pump to produce a brewers’ spent grain slurry having a continuous particle size distribution extending through two different particle size ranges of 100-450 pm and 450-850 pm, wherein the brewers’ spent grain slurry in this two particle size ranges is the high fiber liquid flour.

14. The high fiber liquid flour of claim 13, wherein the second pump is a dispersion pump or colloidal mill.

15. The high fiber liquid flour according to any one of claims 13 to 14, wherein the wet brewers’ spent grain has a moisture content of between 70% and 85% by weight.

16. The high fiber liquid flour according to any one of claims 13 to 15 , wherein the wet brewers’ spent grain is maintained at the temperature of at least 60°C.

17. The high fiber liquid flour according to any one of claims 13 to 16, wherein the brewers’ spent grain slurry has a bimodal particle size distribution.

18. The high fiber liquid flour according to any one of claims 13 to 17, wherein the brewers’ spent grain slurry has a modal particle size within the 100-450 pm range.

19. The high fiber liquid flour according to any one of claims 13 to 17, wherein the brewers’ spent grain slurry has a modal particle size within the 450-850 pm range.

20. The high fiber liquid flour according to any one of claims 13 to 19, wherein the brewers’ spent grain slurry with particle size range of 100-450 pm has the mass percentage (%) of greater than 50 of the total brewers’ spent grain slurry, such as the mass percentage (%) of greater than 80 of the total brewers’ spent grain slurry.21 . The high fiber liquid flour according to any one of claims 13 to 19, wherein the brewers’ spent grain slurry with particle size range of 450-850 pm has the mass percentage (%) of greater than 50 of the total brewers’ spent grain slurry, such as the mass percentage (%) of greater than 80 of the total brewers’ spent grain slurry.

22. The high fiber liquid flour according to any one of claims 13 to 21 , wherein the shearing and grinding the wet brewers’ spent grain step further comprises recirculating the brewers’ spent grain through the second pump.

23. The high fiber liquid flour according to any one of claims 13 to 21 , wherein the shearing and grinding the wet brewers’ spent grain step comprises processing the brewers’ spent grain through two sequential dispersion pumps.

24. The high fiber liquid flour according to any one of claims 13 to 21 , wherein the shearing and grinding the wet brewers’ spent grain step comprises processing the brewers’ spent grain through a dispersion pump followed by a colloidal mill.

25. The high fiber liquid flour according to any one of claims 13 to 24, wherein the brewers' spent grain slurry has a median particle size in the range of 150-350 pm.

26. A food product made from the high fiber liquid flour according to any one of claims 13 to 24 .

27. A system for producing a high fiber liquid flour from brewers’ spent grain, wherein the system comprises:- a buffer vessel or a hopper or inline process, configured to receive wet brewers’ spent grain;- a first pump and a second pump, said first pump being configured to receive a feed stream of the wet brewers’ spent grain and to pump the wet brewers’ spent grain by the first pump to a second pump; wherein the second pump is configured to shear or grind the wet brewers’ spent grain to produce a brewers’ spent grain slurry with a having a continuous particle size distribution extending through different particle size ranges of 100-450 pm and 450- 850 pm, wherein the brewers’ spent grain slurry in this two particle size ranges is the high fiber liquid flour.

28. The system according to claim 27, wherein the system is configured mobile.

29. The system according to one of claims 27 or 28, wherein the system is configured to produce a high fiber liquid flour according to any one of claims 13 to 24, and / or to conduct a method according to any one of claims 1 to 9.

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