BRPI1008871B1 - CONTINUOUS METHOD AND SYSTEM SUITABLE FOR PREPARING CEREAL GRAIN LIQUID EXTRACT - Google Patents

Description

"CONTINUOUS METHOD AND SYSTEM SUITABLE FOR PREPARING A NET EXTRACT OF CEREAL GRAIN" TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method of preparing liquid cereal grain extract. The method according to the present invention may, for example, be suitably used in the brewing industry, for example for must production.

The invention further provides a system comprising a grinding apparatus and a separation device suitable for use in the aforementioned method.

BACKGROUND OF THE INVENTION

In the fermentation industry (brewing) the milling of raw materials before kneading for mash production is usually done by one of the following techniques:. dry milling by roller mill; . dry milling by hammer mill; . wet grinding by maceration and roller mill; . conditioned grinding (similar to dry milling by roller mill, except that the malt moisture level is raised slightly to make the grain husks more collapsible). Pump Dispersion Grinding Each of these operations has its advantages and disadvantages in terms of extract production, oxygen take-up, separation or mass separation performance, downstream processing effect, milled grain enzymatic performance. kneading), hygienic aspects, energy consumption, risk of dust explosion, peel tannin extraction, filtration leakage, etc.

Wet milling has become less popular due to some major disadvantages associated with this type of milling technique, namely remarkably long residence time distributions for kneading and insufficient milling of poorly modified malts. However, wet milling also has some significant advantages over dry milling. Increased safety regulations regarding dust explosion hazards, for example, require preventive measures that have driven up the cost of dry milling operations. Wet milling techniques obviously do not require such measures.

Pump dispersion technology has been investigated as a possible alternative to wet grinding. However the stator rotor combination blazon due to non-malt particles has been found to result in high maintenance costs and unreliable performance.

Hence there is a need for a milling technique that combines the advantages of wet milling (no dust, minimal safety precautions, simple equipment, low capital expenditure) with the simplicity, for example, of the hammer mill process .

SUMMARY OF THE INVENTION

It has been found that the aforementioned objective is achieved by a continuous milling method in which cereal grain particles are disintegrated while being suspended in a liquid, said disintegration being achieved by colliding freely suspended grain particles. with one or more blades which are rotating at a very high tip speed of at least 10 m / s. In the present method, the distance between a tip of said one or more rotating blades and the axis of rotation is in the range of 2-25 cm and the total mechanical energy transferred by one or more rotating blades is in the range of 5-1,000 kJ / kg of dry cereal grain. Thus, the present method employs one or more relatively small rotating blades, which rotate at a very high speed, and which remain in contact with the suspension containing the cereal grain particles for a sufficiently long period of time to achieve a reduction. particle size.

The method according to the present invention provides all the benefits of wet grinding and is no more complex than an extremely robust hammer mill. The present method uses the same principle that is applied in standard kitchen mixers, that is, a blade that rotates at a very high speed. Due to the inertia of the suspended cereal grain particles, the fast turning blade is able to disintegrate these grain particles on impact. Unlike milling techniques that have hitherto been used to pulverize cereal grains on an industrial scale, the disintegration of grain particles in the present method does not rely on the stressing of grain particles between two solid surfaces.

According to another aspect, there is provided a system for preparing liquid cereal grain extract, the system comprising a milling apparatus and a separation device for separating spent grain and liquid extract connected downstream to the milling apparatus in the wherein the milling apparatus comprises a liquid inlet connected with a milling chamber to contain a milled suspension, in which a rotor is received in the milling chamber, the rotor comprising one or more blades extending from the axis of rotation of the rotor, the blade being received in the grinding chamber, in which a distance between a tip of said one or more blades and the axis of rotation is in the range of 2-25 cm, the rotor being connected to a drive unit for rotation, wherein the drive unit is arranged to drive the blade at a tip speed of at least 10 m / s.

The main advantages of the present method and system can be summarized as follows:. capital and maintenance cost savings; . applicable in both batch and continuous fermentation; . short milling times; . hygienic design due to constant flow through the system.

In addition, it has been found that unlike various other milling techniques, the present method can also be used to suitably grind and extract cereal grains with a moisture content exceeding 12%. Finally, it has been unexpectedly found that the present method when used to extract, for example, barley, produces a liquid extract that has a reduced β-glucan content. This reduction in β-glucan levels has a positive effect on product quality as well as downstream processing.

The benefits of the present method are particularly pronounced when employed in industrial scale production of liquid extracts from cereal grain. Thus, the present method is advantageously employed to prepare liquid cereal grain extract by processing cereal grain at a rate of at least 100 kg of dry cereal grain per hour.

DRAWINGS

Figure 1 shows schematically a first embodiment of a system according to the invention.

Figure 2 shows schematically a second embodiment of a system according to the invention.

Figures 3a and 3b show schematically a detail of a blade according to one embodiment of the invention.

Figure 4 shows schematically a third embodiment of a system according to the invention.

Figure 5 shows schematically an alternative arrangement of a grinding apparatus according to the invention. DETAILED DESCRIPTION OF THE INVENTION

Accordingly, an aspect of the invention relates to a continuous method for preparing a liquid cereal grain extract by spraying cereal grain at a rate of at least 100 kg of dry cereal grain per hour, and extracting the cereal grain. sprayed with a liquid, said method comprising:. continuously combine cereal grain with a liquid; . continuously disintegrating the grain particles contained within the liquid by colliding freely suspended grain particles with one or more rotating blades, thereby producing a ground suspension; . continuously transfer at least part of the ground suspension, optionally after further treatment, to a separation device for separation into spent grain and liquid extract; wherein one or more rotating blades are rotating at a tip speed of at least 10 m / s; the total mechanical energy transferred to the milled suspension by one or more rotating blades is in the range of 5-1,000 kJ per kg of dry cereal grain, and the distance between a tip of said one or more rotating blades and the axis of rotation is in the range of 2-25 cm.

The term "cereal grain" as used herein refers to a particular form of a cereal crop, a dried fruit (caryopsis), or a combination of two or more of these materials. The present invention encompasses a method in which the cereal grain employed is a pre-ground cereal grain.

The term "blade" as used herein refers to a solid object which is configured to rotate about an axis of rotation and which usually includes at least two wings (blades) extending radially in different directions, for example, opposites from a center point (of gravity). A requirement of the blade is that it can be properly used to disintegrate the grain particles on impact. In addition, the blade is required to provide stirring action to mix the cereal grain with liquid, thereby assisting in uniform spraying of the grain particles.

The term "disintegrate" as used herein refers to the breaking of a solid particle into two or more solid particles. The term "disintegrate" does not encompass breaking loose loose particles such as agglomerates.

The term "mechanical energy" as used herein refers to the total amount of potential energy and kinetic energy that is transferred to the milled suspension by one or more rotary blades. The amount of mechanical energy that is transferred in the present method can be deduced, for example, from the temperature rise caused by the rotating blades and / or can be calculated from the torque that is employed to rotate the blades.

The words "one or more rotating blades" should be understood to refer to the blades that are moving through the liquid containing the grain particles in a rotating path. According to one embodiment, one or more rotary blades are mounted on a rotary axis on a rotary body, for example within a rotary cylinder. According to another embodiment, which is also encompassed by the present invention, one or more rotating blades are mounted in a stationary body and the liquid containing the grain particles is rotated after the blades, for example under the influence of blades. rotary Of course it is also feasible to enhance the effectiveness of the present method by employing blades that are mounted on a rotating body and rotating the liquid in a direction that is opposite to the direction in which the blades rotate.

The present method is carried out in a continuous manner, meaning that the present process employs an essentially continuous stream of cereal grain and an essentially continuous stream of liquid or, alternatively, an essentially continuous stream comprising cereal grain and which furthermore produces an essentially continuous stream of ground suspension. The portion of the milled suspension, which is transferred to a separation device, is advantageously separated continuously into liquid extract and spent grain. The liquid extract thus obtained may be suitably employed in an operated process, or in batch or continuously, for example in a fermentation process. Thus, the present method can be used in a fermentation process that employs batch operations such as batch must production and batch fermentation. According to a particularly preferred embodiment, the present method is employed in a continuous fermentation process which further includes continuous must boiling, continuous sludge removal and continuous fermentation.

In addition, a system is provided for preparing a liquid cereal grain extract, said system being suitable for operating the method described hereinabove. The system comprises a milling apparatus and a separating device for separating spent grain from liquid extract connected downstream to the milling apparatus, wherein the milling apparatus comprises a liquid inlet connected to a milling chamber to contain a milled suspension, wherein a rotor is received in the grinding chamber, the rotor comprising one or more blades extending from the rotor axis of rotation, the blades being received in the grinding chamber, at which a distance between a tip of said one or more more blades and the rotation axis is in the range of 2-25 cm, the rotor is connected to a drive unit for rotation, in which the drive unit is arranged to drive the blade at a tip speed of at least 10 m /s.

As mentioned hereinbefore, the present method and system may suitably be operated on an industrial scale.

Typically in the present method the cereal grain is sprayed at a rate of at least 150, preferably 200, more preferably at least 300 kg of dry cereal grain per hour.

The present method and system offer the advantage that reduction in grain particle size can be achieved only by the action of the fast spinning blades. Thus, wear and tear as a result of direct or indirect contact between different elements of a grinding device, for example as a result of foreign objects such as stones, is minimized. Accordingly, according to a highly preferred embodiment of the invention, the disintegration of the grain particles under the action of one or more rotating blades does not result from the tensioning of the grain particles between one surface of said one or more rotating blades and another solid surface. Clearly, this aspect distinguishes the present method from wet milling techniques such as wet milling and roller milling, conditional milling and pump dispersion milling.

The present method and system may be advantageously used to achieve a substantial reduction in the particle size of the cereal grain particles. Typically the disintegration of the grain particles under the action of one or more rotating blades causes a reduction in the weighted average mass particle size of the cereal grain by at least one factor 2, preferably by at least one factor 4. More preferably , to one or more rotating blades cause a reduction of said average particle size by at least one factor 8.

The present method and system may suitably be used to prepare a liquid extract from a wide variety of cereal grain materials. Particularly good results are obtained if prior to disintegration under the action of one or more rotating blades the grain particles contained within the liquid have a weighted average mass particle size of 0.5 mm to 1 cm, preferably 1 mm to 8 mm.

The present method and system typically produces a ground suspension in which the particles have a weighted mass average diameter in the range of 50-1000 microns preferably in the range of 100-800 microns.

According to a preferred embodiment of the present method, large (coarse) particles, for example particles having a diameter of at least 0.5 mm, are selectively removed from the milled suspension during or after the grinding operation. and before it reaches the separating device by passing the liquid suspension through a suitable separating element, for example a sieve, a screen, or a cyclone. The terms "selectively removed" or "selectively separated" mean that coarse particles are removed and smaller particles remain in the suspension. Even more preferably, particles having a diameter of at least 1.0 mm are removed from the milled suspension. More preferably, particles having a diameter of at least 2.0 mm are removed. The large particles removed from the milled suspension are preferably recirculated to the milling step, notably by introducing these separate particles into the liquid containing the suspended grain particles. According to a particularly preferred embodiment, the separated particles are recirculated in a continuous manner.

A feedback loop may be supplied from downstream of the milling apparatus upstream of the milling apparatus. In one embodiment a return duct may resume suspension containing large particles to at least one milling apparatus according to the present invention. It should be understood that the latter embodiment includes recirculation of the separated particles directly to the milling apparatus or upstream of the milling apparatus (e.g., to a mixing device in which the fed grain particles are combined with the liquid).

The liquid and cereal grain are suitably combined in the present method to form a suspension containing 6-50 wt%, preferably 10-45 wt% and more preferably 15-40 wt%. dry matter. Here dry matter includes both dissolved and undissolved materials.

The liquid which is combined with the cereal grain is preferably an aqueous liquid. The aqueous liquid employed may be fermentation water. The present invention, however, also encompasses use of a stream of circulated aqueous liquids that originate from anywhere in the fermentation process. An example of such recirculated aqueous liquid is wash water which has been used in the present method for washing spent grain.

[00036] The grinding efficiency of the present method and system is affected by the volume of the chamber in which the disintegration of the grain particles under the action of the rotating blades occurs. If the volume is large, it may take an unacceptably long time to achieve a substantial particle size reduction. If the volume is too small, substantial particle size reduction can also be difficult to achieve as the residence time will be very short, so that only a fraction of the grain particles will be able to collide with the rotating blades. It has been found that very efficient cereal grain spraying can be achieved by passing the combined cereal and liquid stream through a relatively small volume chamber sequence, where each chamber contains one or more rotary blades as defined hereinbefore. Alternatively, efficient milling can be achieved by passing the combined stream through a tube containing a sequence of two or more, preferably a sequence of three or more rotary blades. The tube may be straight but may also be bent. The cross section of the tube may take various forms, for example, circular or relatively square.

Hence, according to this preferred embodiment, the grain particles are disintegrated by passing the liquid supporting the grain particles through two or more, even more preferably through three or more, spray chambers containing each one. , one or more of the rotating blades. The residence time within each of the spray chambers is preferably within the range of 0.1-10 minutes, more preferably within the range of 0.1-4 minutes. More preferably, the residence time within each of the spray chambers is in the range of 0.2-2 minutes.

The rotary blades employed in the present method and system are suitably mounted on a rapidly rotating shaft. Preferably the present method and system employ one or more rotary blades each comprising at least two radially extending wings (wings) in different, e.g. opposite, directions from a gravitational center point coinciding with the axis of rotation.

[00039] The wings of the rotating blades include front edges and rear edges. Preferably at least a portion of the front edges of the blade wings is chamfered to provide a cutting edge. By providing the front edges of the wings with a cutting edge, the effectiveness of rotating blades in disintegrating grain particles can be further enhanced.

As explained hereinbefore, one or more blades employed in the present method and system advantageously provide a stirring action during operation. When one or more blades rotate within the liquid supporting the suspended grain particles, the cutting edges of the blades define a cutting path and the wings generate flow of the liquid and the grain particles. The flow generated by the wings due to the rotation of one or more blades brings the liquid and suspended grain particles through the cutting path to homogeneously mix these components and to disintegrate the entrained grain particles into the liquid using the cutting blades.

According to one advantageous embodiment, one or more rotating blades act as stirring impellers, that is, the blades act as rotating wings and generate a difference in pressure between the front and rear surfaces of the blades. As a result of the blending action of the blades disintegrated particles will be pushed away by the rotating blades so that they can be replaced by other particles.

According to a particularly preferred embodiment, the one or more blades comprise at least two blade wings which are twisted, pitched, or otherwise shaped such that the front edges are oriented vertically above or below the edges. rear edges when the axis of rotation is vertical. If, for example, the blade wings are twisted such that the front edges are oriented vertically above the rear edges, then rotation of the mixing blade repeatedly backs the liquid that includes the grain particles through the cutting path. . In this way, rotation of the mixing blade continuously brings the grain particles down through the cutting path and thereafter pushes the particles upwards along the inner surface of the spray chamber. Consequently, the grain and liquid particles are mixed homogeneously, since the grain particles are continuously ground and mixed with the spray chamber contents by rotating the blade.

According to the particularly preferred embodiment, one or more blades comprise two or more wings, whose front edges define cutting paths, and wherein said blade wings are oriented at compound angles to the plane running perpendicular to the axis. rotating through the center of gravity of the blades to provide the mixing blade with composite cutting paths.

Advantageously, each wing is twisted, or otherwise shaped, such that its front edge is oriented vertically above or below its rear edge, and tilted such that its distal end is vertically oriented. above or below the center point when the axis of rotation is vertical. According to a particularly preferred embodiment, the front edge of the blade wings is vertically oriented above its rear edge and its distal end is vertically oriented above or below the center point.

Up to a threshold, the greater the wing angles and, more importantly, the wing twists, the greater the amount of lift associated with the mixing blade. The blade wings may be twisted along the entire length of the wing or alternatively a portion of the blade wings may be twisted to generate proper lift. Typically, the angle of inclination from the front edge to the rear edge of the blade wings does not exceed 60 °, more preferably does not exceed 45 °, the inclination angle being defined with respect to a horizontal plane assuming a vertical axis of rotation. . More preferably, the maximum angle of inclination from the front edge to the rear edge is in the range of 5-30 °.

The blade wings employed in the present process advantageously extend radially outwardly from an axis of rotation. The blade wings may extend outward at an up or down angle to the radial plane. This upward or downward angle to the radial plane preferably is within the range of 5-70 °, more preferably within the range of 10-45 °. Preferably a wing tip portion is inclined with respect to the radial plane at angles mentioned above. Typically, said tip portion represents less than 60%, more preferably less than 50%, of the blade wing length.

In an advantageous embodiment, the one or more rotary blades comprise two or more blade wings extending in the same radial direction at different up and down angles. This blade wing arrangement offers the advantage that increases the efficiency of the grinding action.

Each blade wing has an effective width and length measured between the axis of rotation and the distal ends of the wingtips, the ratio of effective width to wing length being in the range 1: 1 to 1. : 20, preferably in the range of 1: 2-1: 15.

As mentioned hereinbefore, the rotary blades employed in the present method and system are rotatable at a very high speed. Typically one or more rotary blades are rotating at a speed of at least 2,000 rpm, more preferably at least 10,000 rpm. The tip velocity of one or more rotary blades typically is at least 12 m / s, more preferably at least 15 m / s, more preferably at least 20 m / s, even more preferably at least 50 m / s, more preferably at least 50 m / s. minus 70 m / s.

The benefits of the present invention are achieved by employing relatively small rotary blades. On the one hand, it is important to employ a rotating blade that is long enough to ensure that over a significant portion of the blade length the impact with which the blade hits the grain particles is sufficient to disintegrate these particles. At the same time, however, the blade length is limited to a maximum since the torque required to rotate the blade at high tip speed increases exponentially as the blade length increases, and also since the long blades are much more vulnerable when operated at high rpm. Typically the distance between a tip of one or more rotating blades employed in the present method and the axis of rotation, that is, the length of said one or more blades is within the range of 2.5-20 cm, more preferably within the range. 2.5-18 cm, and more preferably within the range of 3-15 cm. According to a particularly preferred embodiment, the tips of all rotary blades rotating at a tip speed of at least 10 m / s, especially at a tip speed of at least 20 m / s, are located within 25 cm. more preferably within 20 cm, even more preferably within 18 cm, and most preferably within 15 cm of the axis of rotation.

To ensure that the present method can be operated with little maintenance it is advisable to employ rotating blades that are made of a shear-resistant material selected from the group consisting of metals, ceramics, synthetic polymers, diamonds, and combinations thereof. .

According to a particularly preferred embodiment, one or more rotary blades has a thickness of 0.1-1 cm, more preferably 0.2-0.8 cm, and most preferably 0.25-0, 6 cm. It is advantageous to employ a blade of minimum thickness, as this minimizes rotating friction and maximizes the cutting ability of the blade. Naturally, however, the thickness should be sufficient to ensure an adequate operating life of the rotary blade.

[00053] The temperature of the liquid that is combined with the cereal grain prior to disintegration by the action of the rotating blades may vary within a wide range. Typically, the temperature of the liquid when it is combined with the cereal grain is within the range of -5 to 100 ° C, preferably within the range of 10 to 60 ° C.

To achieve a significant reduction in the particle size of the cereal grain, a significant amount of mechanical energy must be transferred by one or more rotary blades to the milled suspension. Typically the total amount of mechanical energy that is transferred to the milled suspension by one or more rotary blades is at least 8, more preferably at least 10, and most preferably at least 15 kJ per kg dry cereal grain. The present method offers the advantage that considerable reduction in cereal grain size can be achieved with a limited amount of mechanical energy transfer. Accordingly, the total mechanical energy transferred to the milled suspension by one or more advantageously rotating blades does not exceed 800, more preferably does not exceed 500, more preferably does not exceed 300 kJ per kg of dry cereal grain.

Mechanical energy transferred to the milled suspension by one or more rotating blades, in the absence of significant cooling or evaporation, will cause the milled suspension to rise in temperature. In the present method the disintegration of the grain particles is typically accompanied by a temperature rise of the ground suspension of less than 100 ° C, more preferably less than 60 ° C, and more preferably less than 30 ° C. To avoid significant temperature rise, the grain particle suspension may be cooled during the grinding operation. According to a preferred embodiment, however, the disintegration of the grain particles is achieved without cooling the suspension.

The milled suspension may suitably undergo one or more additional treatments before being transferred to a separation device for separation into spent grain and liquid extract. According to a preferred embodiment, prior to separation into spent grain and liquid extract, the milled suspension is subjected to a maceration operation to allow enzymes to break down starch extracted into sugars, typically maltose.

Separation into spent grain and liquid extract can be suitably accomplished by any solid-liquid separation technique known in the art. Preferably, said separation is achieved by one or more separation devices selected from a ground malt filter, a centrifuge, a clarification tank, a sieve. The present method is particularly suitable for preparing a ground suspension which can be separated very efficiently by means of a ground malt filter. Hence, in a particularly advantageous embodiment, the present method employs a mesh filter to separate the milled suspension into spent grain and liquid extract.

Examples of cereal grains which may be suitably processed by the present method include barley, sorghum, rice, maize, buckwheat, rye, millet, malted versions of these cereal grains, and combinations of these grains. According to a particularly preferred embodiment, the cereal grain of the present method includes barley, especially malted barley.

In addition, the invention is illustrated with reference to the figures in which: Figure 1 schematically shows a first embodiment of a system according to one embodiment of the invention; Figure 2 schematically shows a Figure 3a and 3b show schematically a detail of a blade according to one embodiment of the invention. Figure 4 schematically shows a third embodiment, and Figure 5 shows schematically a an alternative arrangement of a grinding apparatus according to the invention.

Figure 1 provides a schematic example of an embodiment of the invention. Figure shows a cross section of a milling apparatus 1. In addition, figure 1 shows schematically a reactor 50, for example a heat exchanger, and a separation device 20, for example a device for separating solids from liquid according to the invention. A system comprising a milling apparatus 1, a reactor 50 and a separation device 20 may be used in the preparation and production of a liquid extract of a cereal grain such as must.

The system according to the invention comprises one or more milling apparatus 1. In one embodiment, the system according to the invention comprises a series of two or more milling apparatus 1. The two or more milling apparatus 1 are preferably connected in series. It is also feasible to employ a milling apparatus which contains a sequence of rotating blades, for example using a tube holding two or more rotating blades. Using two or more milling apparatus or using a rotary blade sequence enables efficient disintegration of the grain particles, as will be explained in more detail here below.

In Figure 1 a liquid is introduced into a milling apparatus 1 through an inlet 2 into a milling chamber 3. In the embodiment according to the figure, the milling chamber 3 is a vessel or container. A second inlet 4 schematically represents the inlet for feeding cereal grain to the grinding chamber 3. While inlets 2, 4 are shown in a specific position, the skilled person is able to position inlets 2, 4 in desired positions. In one embodiment, one of the inlets brings the liquid or cereal grain to an average position of a milling chamber 3, for example, close to the blades 30, 31. In another embodiment a mixture of liquid and cereal grain is introduced into the apparatus. 1 through input 2.

The milling chamber 3 contains a cereal grain suspension. The suspension is shown in the figure having a fluid level 13. However, in a preferred embodiment, the grinding chamber 3 is completely filled with fluid.

[00064] It is possible to control the incoming flow of liquid and grain into the grinding chamber. Parameters representing inlet flow quantities (shown schematically in Figure 1 in the form of regulating valves 44 or dosing screw 45) may be collected on a controller 5 comprising a processor and memory (not shown). Controller 5 is connected, for example wirelessly, with metering device (not shown) to measure the amount of input flow. The regulating valve 44 as well as the metering screw 45 may comprise a means for controlling the amount of inlet flow to the grinding chamber 3.

The controller 5 is connected with, and can control a drive unit 6. The drive unit 6 schematically represents a unit that is capable of bringing rotor 7 to rotation at a desired speed. The drive unit 6 may be an electronically controlled motor. It can comprise a transmission.

The rotor 7 comprises a shaft 8 extending into the grinding chamber 3, suspended on a sealed shaft bearing, shown schematically 12. In one embodiment the drive unit 6 is also received in the grinding chamber. Milling 3. In one embodiment a transmission is received in the grinding chamber 3.

[00067] In one embodiment the rotation axis of drive unit 6 is connected to axis 8 via a transmission. In one embodiment a drive unit 6 may be used to drive more than one axis 8 of different milling apparatus 1. In one embodiment a milling apparatus 1 comprises more than one axis 8 having different blades 30, 31. ] Two blades 30, 31 are mounted on shaft 8. A blade 30, 31 is a replaceable unit that can be locked and unlocked on shaft 8. In the illustrated example, a glove 46 is interposed between blades 30, 31. The versed person You will be able to arrange different types of mounting systems for mounting and locking a blade 30, 31 to shaft 8.

In one embodiment the blade 30 comprises three blade wings 9-11 as shown in the embodiment of Figure 3b. The distance 15 from the axis of rotation 14 to the tip 16 of a blade is at least 2 cm. Preferably the distance 15 is at least 5 cm, more preferably at least 10 cm. In one embodiment the blades have a maximum length 15 of at most 25 cm, more preferably at most 20 cm. The blade 30 is arranged and constructed for rotation in a clockwise direction 28 since a sharp edge 29 will form the front edge of wings 9-11 during rotation. In addition, the distal portion 27 of wings 9-11 comprises an upwardly folded fin 26. Rims 26 and sharp front edges 29 are arranged and constructed to spray the grains present in the fluid contained in the grinding chamber. Fins 26 are further arranged and constructed to agitate fluid in operation.

According to the invention, the tip 16 will have a minimum velocity of at least 10 m / s to create a mixer effect during grinding.

Figure 3a shows a different embodiment of a blade 90. The blade 90 comprises a central glove body 91 having 4 wings 92-95 extending radially from the glove body 91. Each wing 92-95 comprises a generally radially extending portion 96, and a more distal tip portion 97 of portion 96 extending at an angle α up or down relative to the radial plane 98. In one embodiment the wings 92- 95 are also provided with a fin. This is not shown in figure 3a. The wing or other part of the wing extending in a direction parallel to the axis of the shaft 14 may cause a fluid disturbance during rotation causing mixing of the fluid in use, allowing grinding of the complete fluid contained within the grinding chamber 3.

In one embodiment the fins are arranged and constructed to cause aspiration and push fluid into and from the wing during rotation to cause agitation in the fluid. In one embodiment the shaft 8 extends from a lower end of the grinding chamber 3 upwards into the fluid contained in the grinding chamber 3. The blades extend from the shaft near a lower surface of the grinding chamber.

Controller 5 can control drive unit 6 to bring blades for rotation. The drive unit is capable of rotating the blade wing tip 16 to at least 10 m / s, preferably at least 15 m / s. This will allow for an industrial-scale kitchen mixer effect resulting in a system of preparing a liquid cereal grain extract by spraying cereal grain at a rate of at least 100 kg of dry cereal grain per hour. which is more effective than prior art systems.

Preferably apparatus 1 is arranged for continuous feeding of liquid and cereal grain.

Figure 2 shows a different embodiment in which a mixing chamber 60 is arranged upstream of a series of three milling apparatuses 61, and in which other elements are similar to the first embodiment. The mixing chamber 60 comprises two inlets 62, 63 for cereal grain and for water or an aqueous liquid, which are brought together in a generally drum-shaped container comprising a mixing device 64, shown schematically. The mixing device comprises a blade 65 and a drive unit 66. The drive unit 66 and the blade 65 are arranged to mix the fluid and the grain. A preferably low rpm is used for mixing. In one embodiment the mixing chamber 60 is arranged to perform pre-processing of the suspension grinding. In the embodiment shown, the mixed suspension flows to one of the three milling apparatuses 61 having a similar adjustment to the milling apparatus 1.

In operation, the blades 30, 31, in particular the tips 16 of the blade wings 9-11 will disintegrate grain particles suspended in the liquid contained in the grinding chamber 3. The blade wings will, due to the high angular velocity In particular due to the high speed of the tips 16 of the blade wings 9-11, transfer a substantial amount of kinetic energy to the suspension. Preferably the total mechanical energy transferred is at least 5 kJ per kilogram of dry cereal grain. Controller 5 is capable of monitoring that the rotational speed is sufficient to transfer the appropriate amount of kinetic energy to the suspension, that is, sufficient kinetic energy to disintegrate grain particles in the suspension.

To increase the mixing of the suspended particles as a result of the operation of the grinding apparatus, a grinding chamber could comprise one or more baffles 74, 75 extending, in the embodiment shown, radially inwardly from the chamber wall 3 Grinding The baffles 74, 75 may be part of a baffle body that is positioned in the grinding chamber 3.

The first milling apparatus shown in Figure 1 has an outlet 18. The outlet 18 may comprise a valve 19 (or a pump) which may be controlled by the controller 5. The outlet 18 also allows the transport of grain suspension to the nearby grinding appliance. The latter grinding apparatus has an outlet 21 allowing transport of the milled suspension to a reactor chamber 50 and further downstream to a separation device 20. The separation device 20 in this embodiment comprises a schematically illustrated mesh 22 upstream of the exit 23.

In one embodiment the separating device 20 further comprises a centrifuge. The person skilled in preparing liquid cereal grain extracts will be familiar with different settings which may be used in combination with a milling apparatus according to the embodiment shown.

In one embodiment the outlet 18 is generally positioned at a height midway from the grinding chamber 3. This will allow continuous transfer of ground fluid from the chamber 3. Along the bottom side the heavier suspended particles will gather , while near a higher end there will be fewer suspended particles.

Although Figure 1 shows a net level 13, it is also possible and in some preferred embodiments to operate the chambers without a higher space gas phase present in the grinding apparatus 1.

In one embodiment the transfer between the grinding apparatus 1.61 and towards a reaction chamber 59 is continuous. Subsequent transfer steps could be either batch and / or continuous.

Although Figure 1 illustrates the system according to the invention in a very schematic manner, the skilled person will be able to improve the embodiment shown for an industrial scale using the invention as discussed herein. In particular, the skilled person is able to provide the system according to the invention in a brewery.

Figure 4 schematically illustrates a third embodiment of a system according to the invention. Fig. 4 shows schematically a system comprising a mixing apparatus 100 and a grinding apparatus 104, wherein said grinding apparatus comprises a single grinding chamber 105 in which three drive units, shown schematically, and rotors 101, 102, 103 are received. Cereal grains 120 and water or an aqueous liquid 121 are added to the mixing chamber 112 to be converted into a suspension.

The mixing apparatus 100 comprises the rotor 111 received in the mixing chamber 112 in which also the drive unit 113 connected to the rotor 111 is received completely in the mixing chamber 112.

The grinding chamber 105 comprises three grinding units 106-108 schematically separated by partition panels 109-110. The partition panels 109-110 are advantageously arranged such that large particles contained in the suspension flowing through the grinding chamber 105 are retained in grinding units 106 and 107 respectively. In the illustrated example, the large particles are retained by the partition panels 109 and 110 since the suspension level 122 in the mixing chamber 150 is high enough to allow the suspension to overtake these panels until the next grinding unit, but not high. enough to carry with it the large particles contained in it. Thus, large particles are retained in the grinding unit 106 and grinding unit 107 until they have been disintegrated by the grinding action to a particle size that can pass the partition 109 or partition panel 110.

Downstream of the grinding chamber 105, a pump 115 supports suspension flow according to the arrows shown in the figure. Other large particle separation may be achieved in the separating element 116 downstream of the pump 115. The recycle conduit 125 may produce a separate large particle feedback loop towards one or more of the grinding units 106, 107.108.

The suspension containing properly disintegrated particles flows downstream to reactor 117 and from it to a spent grain separator 118 to obtain liquid extract 119.

Figure 5 illustrates a different embodiment of a grinding apparatus 130. A drive unit 131 is connected to a frame (not shown). In addition, the stationary element 135 is fixedly connected to that structure. Drive unit 131 drives rotor body 133 which carries blades 136 for rotation according to arrow 138. Rotor body 133 is rotatably mounted 134 on stationary element 135. Here the stationary element 135 is positioned in position of the axis of rotation. The tip of the blades 136 is positioned close to 139. 100090] The invention is further illustrated by the following non-limiting examples: EXAMPLES Example 1 100091] A direct current of 128 kg / h of ntalte was introduced into a grinding chamber along with a continuous stream of 283 kg / h of fermentation water. In the milling chamber which had a volume of 6 liters, a blade with a diameter of 8.5 cm rotated at 21,500 rpm. Product stream from this chamber was transferred to two similar series-operated chambers, and in identical process adjustments. This grinding system was brought to the constant state by grinding for at least 20 minutes under constant power input conditions. The product from the third grinding chamber was collected and poured into a 100 liter stirred mains vessel. A typical maeeration profile was used with a protein rest for 20 minutes at 58 ° C, a heating phase to reach 66 ° C in 15 minutes, a saccharification rest at 66 ° C for 25 minutes, again heating for 15 minutes to 76 ° C and a final rest at this temperature for 10 minutes. Hereafter the ground malt was transferred to a two chamber ground malt filter. The ground malt filter was operated in the same manner as with hammered malt.

The resulting must was pumped into a boiling vessel and the must was boiled for 90 minutes. After separation of hot sludge and cooling of the roast to fermentation temperature, oxygen and yeast were added and normal beer fermentation was performed. Must samples were taken and analyzed, indicating a specific must weight of 12.9% (weight / weight).

[00094] Beer end product was packaged in suitable containers (bottles) and analyzed under beer quality parameters. Analysis on wort parameters and beer parameters indicated good inaccuracy performance and good product quality. Of particular interest is the amount of fermentable sugars formed during the maceration process, indicating the availability of starch for enzymes induced by malt grain milling. In this example a value of 69.8% (w / w) of the carbohydrates was fermentable sugars, resulting in an apparent final attenuation limit of 86% (w / w).

Example 2 Continuous streams of 200 kg / l malt and 400 kg / h water are introduced into a continuously shaken mixing vessel with an impeller to obtain a suspension. The mixture is transferred to a first mixing chamber. milling that has a volume of 6 liters. An 8.5 cm diameter blade is continuously rotated at 21,500 rpm in the chamber. Product stream from this chamber is transferred to two similar series-operated chambers at identical process settings.

Following this sequence of mixing chambers, a positive displacement pump transfers the mixture to the 600 liter volume vertical conversion reactor. The reactor is equipped with a vertical shaft on which discs are mounted to achieve mixing. A temperature profile along the height of the reactor is applied with a protein stand at 58 ° C, a saccharification stand at 67 ° C, and a final stand at 78 ° C. Thereafter the ground malt is transferred to a decanter centrifuge to remove particles.

The resultant must is pumped towards a boil reactor of the same geometry as the conversion reactor, and the must must be boiled for 60 minutes at 103 ° C. After hot sludge separation and wort cooling to fermentation temperature, oxygen and yeast are added and a normal beer fermentation is performed.

Claims (18)

1. A continuous method for preparing a liquid cereal grain extract by spraying the cereal grain at a rate of at least 100 kg of dry cereal grain per hour and extracting the pulverized cereal grain with a liquid comprising: continuously combine cereal grain with a liquid; continuously disintegrate the grain particles contained within the liquid by colliding freely suspended grain particles with one or more rotating blades, thereby producing a ground suspension; continuously transfer at least a portion of the milled suspension, optionally after further treatment, to a separating device for spent grain and liquid extract separation; wherein one or more rotating blades are rotating at a tip speed of at least 10 m / s; the total mechanical energy transferred to the milled suspension by one or more rotating blades is in the range of 5-1,000 kJ per kg of dry cereal grain, and the distance between the tip of said one or more rotating blades and the rotating axis is in the range of 2-25 cm. Method according to claim 1, characterized in that the disintegration of the grain particles under the action of one or more rotating blades does not result in the tensioning of the grain particles between a surface of said one or more rotating blades and another. solid surface. Method according to Claim 1 or 2, characterized in that the disintegration of the grain particles by one or more rotary blades results in a reduction in the weight-weighted average particle size of the grain by at least a factor 2, preferably by at least one factor 4. Method according to any one of claims 1 to 3, characterized in that prior to disintegration under the action of one or more rotary blades the grain particles contained within the liquid have a mass-weighted average particle size of 0, 5 mm to 1 cm. Method according to any one of claims 1 to 4, characterized in that the particles within the milled suspension have a mass weighted average diameter in the range of 50-1000 microns, preferably in the range of 100-800 microns. Method according to any one of claims 1 to 5, characterized in that the liquid and the cereal grain are combined to form a suspension containing 6-50% by weight of dry matter. Method according to any one of claims 1 to 6, characterized in that the liquid is an aqueous liquid. Method according to any one of claims 1 to 7, characterized in that one or more rotating blades are rotatable with a tip speed of at least 15 m / s, more preferably at least 20 m / s, more preferably at least 50 m / s, more preferably at least 70 m / s. Method according to any one of claims 1 to 8, characterized in that the distance between one end of one or more rotating blades and the axis of rotation is within the range of 2.5-20 cm, preferably within the range. 3-15 cm range. Method according to any one of claims 1 to 9, characterized in that the total mechanical energy transferred to the milled suspension by one or more rotary blades is in the range of 8-500 kJ per kg of cereal grain. dry, more preferably in the range 10-300 kJ / kg. Method according to any one of claims 1 to 10, characterized in that the cereal grain is selected from barley, sorghum, rice, maize, buckwheat, rye, millet, malted versions of these cereal grains, and combinations. of the same. System for preparing a liquid cereal grain extract using the method as defined in any one of claims 1 to 11, characterized in that it comprises at least one milling apparatus (1) and a separating device (20) for separating spent grain of liquid extract connected downstream to the milling apparatus (1), wherein the milling apparatus (1) comprises a liquid inlet (2) connected to a milling chamber (3) to contain a milled suspension in which a rotor (7) is received in the grinding chamber (3), the rotor (7) comprising one or more blades (30, 31) extending from the rotor axis (14) of the rotor, the blades (30, 31) being received in the grinding chamber (3), in which a distance (15) between a tip (16) of said one or more blades (30, 31) and the axis of rotation (14) is in the range of 2- 25 cm, the rotor (7) being connected to a drive unit (6) for rotation in which the drive unit (6) is arranged a to drive one or more blades (30, 31) at a tip speed of at least 10 m / s. System according to claim 12, characterized in that the system further comprises a controller (5) for controlling the drive unit (6), in which the controller (5) is arranged and constructed to control the drive unit. drive (6) to transfer a total of mechanical energy to the milled suspension by one or more blades (30, 31) in the range of 5,000 kJ per kg of dry cereal grain suspended in the liquid. System according to Claim 12 or 13, characterized in that the one or more blades (30, 31) comprise two or more wings (9, 10, 11) whose front edges define cutting paths (24) and wherein said blade wings are oriented at compound angles with respect to the plane running perpendicular to the axis of rotation (14) through the center of gravity of the blades (30, 31) to provide the mixing blade with compound cutting paths. System according to any one of claims 12 to 14, characterized in that the system further comprises a reactor (50) in which the separating device (20) is a ground malt filter, a centrifuge, a tank of clarification or a sieve. System according to Claim 15, characterized in that the milling apparatus (1) comprises a sequence of one or more milling units (106, 107, 108) and a separation unit (109, 110, 116). ) positioned downstream of a grinding unit (106, 107, 108) upstream of reactor (50), said separation unit being capable of selectively separating coarse particles from the ground suspension, said coarse particles having a diameter of at least 0.5 mm, more preferably at least 1 mm, and more preferably at least 2 mm. System according to claim 16, characterized in that the system comprises a recycle conduit (125) for recirculating separate coarse particles from the separation unit (109, 110, 116) up to or upstream of one or more of the milling units (106, 107, 108). System according to claim 16 or 17, characterized in that the system comprises a sequence of two, or more preferably 3 or more, milling units (106,107,108).