CONTINUOUS SEED GERMINATION METHOD AND GERMINATION TOWERS FOR IMPLEMENTING THIS METHOD

Abstract

The invention relates to a method for continuous seed germination carried out in a germination tower containing: - an inlet for soaking seeds located at the top of the germination tower; - an outlet for germinating seeds located at the bottom of the germination tower; - a germination chamber located between the inlet for soaking seeds and the outlet for germinating seeds, which contains a number of horizontal inlet tubes positioned across the height and width of the germination chamber and a number of horizontal outlet tubes positioned across the height and width of the germination chamber; this method comprises the following steps: a) continuously feeding soaked seeds through the inlet for soaking seeds into the germination tower, the soaked seeds having a moisture content of 28 to 48% by mass; b) allowing the seeds to move downward by gravity through the germination chamber and between the inlet and outlet tubes while introducing humid air through the inlet tube and removing air through the outlet tube; c) continuously removing germinating seeds from the outlet for germinating seeds; In which the residence time of seeds in the germination tower is 12-120 hours.The invention also relates to a germination tower for implementing this method.

Description

[0001] CONTINUOUS GERMINATION OF GRAIN

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to a method of continuously germinating grain. The method may suitably be used for the production of malt. The invention also relates to a germination tower that can be used for carrying out this method.

[0004] BACKGROUND OF THE INVENTION

[0005] Malting is the process of steeping, germinating and drying grain to convert it into malt. Malt is used to make beer and whisky. Barley is the most commonly malted grain, though wheat, rye, oats, rice, and corn are also used.

[0006] Steeping is the start of the active malting process. Steep water is added to cover the grain and the grain moisture content increases from around 12% to between 40 and 45%. In a modern pneumatic malt house, the grain is alternatively submerged (wet stand) and then drained (an air rest) for two or three cycles to achieve the target grain moisture content and chit count. The first visible sign of germination is the appearance of rootlets known as "chit"; the proportion of chitted grains indicates the progress of the steeping process. At the end of steeping the grain is "cast-out" to germination. Cast-out may be done as a slurry during a wet stand or as moist grain during an air rest.

[0007] The aim of germination is to grow the grains. This allows the development of malt enzymes, and these enzymes modify the structure of the endosperm by breaking down the cell walls and the protein matrix. The enzymes produced during germination are needed to break down the starch for the brewer or distiller during the mashing process.

[0008] Germination is typically carried out in a batch process. A grain bed is maintained at a constant temperature of between 10 and 16 °C by the constant supply of fresh humidified air. Turners move through the grain bed to keep it loose to allow for sufficient airflow. Several types of equipment can be used to produce the malt. Traditional floor malting germinates the grains in a thin layer on a solid floor, and the grain is manually raked and turned to keep the grains loose and aerated. In a modern malt house the process is more automated, and the grain is germinated on a floor that is slotted to allow air to be forced through the grain bed. Large mechanical turners, e.g., Saladin boxes, keep the much thicker bed loose with higher productivity and better energy efficiency.

[0009] Efforts have been made to carry out germination in a continuous manner. US 3,205,152 describes an apparatus for the production of malt, utilizing a column, wherein the material treated passing vertically through said column by its own weight is subjected to different treatments, characterized in that there is provided in said column a plurality of grids one above the other, each grid extending transversely of the entire inside diameter of said column and consisting of a single layer of rods in side-by-side relationship, the respective adjacent rods of each grid being capable of being set in opposing horizontal motion, the mutual spacing of said rods being such that when the rods move in opposite directions, the material to be treated flows through, but when the rods are stationary, the flowing movement is largely arrested. The grid rods can be provided in the form of tubes having apertures in the surfaces thereof, thereby permitting the introduction of gas for wetting and for suction. Along the column and below the locations at which the grids are incorporated, shutoff elements are provided, whereby the column can be separated sectionally from its remaining parts in such a manner permitting a batch operation.

[0010] US 4,048,019 describes an installation for continuously producing green malt from barley, comprising a container having a top with means for receiving barley, a plurality of superposed, substantially horizontal grids of stationary parallel hollow tubes extending between the walls of the container at different levels throughout the container, the tubes of adjacent grids being angularly offset in relation to each other, the tubes being connected in a closed circuit to a supply system for cooling medium, whereby the germinating barley may be cooled solely through contact with the tubes, and a bottom on the container including means for dispensing green malt.

[0011] It is also known to continuously dry grains in a drying tower. US 2012 / 090722 describes a grain drying tower comprising:

[0012] • a first vertical sidewall;

[0013] • a second vertical sidewall opposite the first vertical sidewall; and

[0014] • a plurality of perforated air ducts positioned within the grain drying tower extending horizontally between the first vertical sidewall and the second vertical sidewall; wherein each of the plurality of perforated air ducts includes: o a first end at the first vertical sidewall that is either blocked to form a blocked end or open to form an entry end; and o an opposite second end at the second vertical sidewall that is open to form an exit end if the first end is a blocked end and is blocked to form a blocked end if the first end is an open entry end; wherein air flows into the open entry ends at the first end of the plurality of perforated air ducts, continues through a portion of grain stored in the grain dryer tower, and flows out the open exit ends of the perforated air ducts thereby drying the grain.

[0015] DK 152863 describes an installation for drying granular material, e.g. cereals or seeds, comprising a drying shaft with means for feeding moist material at the top, means for removing dried material at the bottom and means for conveying drying air downstream through at least a part of the shaft, wherein there are means for establishing a free surface of the material and means for supplying hot drying air to the free space above the free surface, characterised in that a number of transverse elements with intermediate slits form the bottom of an upper receiving chamber to which the moist material is supplied, and in that for each slit there is a damper for regulating the outflow of material from the slit, arranged in such a way as to maintain a free space with free fall of the material until it reaches the free surface of the material.

[0016] WO 99 / 45092 describes a process for continuous malting of cereal grain material, wherein the material is mainly transported on inclined conveyor tracks with alternating directions of movement as a material stream that moves downwards by gravity, is subjected to ventilation, cooling, humidification and drying media, and is discharged as malt through a discharge device, the material stream forming a downward-flowing material layer, characterized in that in the transfer area between two conveyor tracks the downward-flowing material layer is section-wise divided in at least one upper and one lower partial stream and in that the partial streams are then brought together again.

[0017] SUMMARY OF THE INVENTION

[0018] The inventors have designed a germination tower for the continuous germination of grain and a method of continuously germinating grain in such a germination tower. This method of continuously germinating grain is carried out in germination tower comprising: an inlet for steeped grain located in the top of the germination tower; an outlet for germinated grain located in the bottom of the germination tower; a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising a plurality of transverse inlet ducts that are positioned across the height and width of the germination chamber and a plurality of transverse draw-off ducts that are positioned across the height and width of the germination chamber; and the method comprises the following steps: a) continuously feeding steeped grain via the inlet for steeped grain into the germination tower, said steeped grain having a moisture content of 28 to 48 wt.%; b) allowing the grains to move downwards in response to gravity through the germination chamber and to pass between the inlet ducts and the draw-off ducts while introducing humid air via the inlet ducts and withdrawing air via the draw-off ducts; c) continuously removing germinated grains from the outlet for germinated grains; wherein the residence time of the grains in the germination tower is 12-120 hours.

[0019] The continuous germination method of the present invention offers the advantage that uniform germination is achieved due to the fact that the grains moving downwards through the germination tower are exposed to identical conditions (temperature, relative humidity, oxygen and carbon dioxide levels).

[0020] The invention also provides a germination tower for carrying out the aforementioned continuous germination method, said germination tower comprising:

[0021] • an inlet for steeped grain located in the top of the germination tower;

[0022] • an outlet for germinated grain located in the bottom of the germination tower;

[0023] • a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising (i) a plurality of transverse inlet ducts with one or more air exit openings that are positioned across the height and width of the germination chamber; and (ii) a plurality of transverse draw-off ducts with one or more air entry openings that are positioned across the height and width of the germination chamber;

[0024] • an air pump for generating an air flow from the plurality of transverse inlet ducts to the plurality of transverse draw-off ducts, said air pump being position upstream of the transverse inlet ducts or downstream of the transverse draw-off ducts;

[0025] • an air humidifier that is positioned upstream of the transverse inlet ducts.

[0026] FIGURES

[0027] Figure 1 schematically depicts a germination tower according to the invention Figure 2 schematically depicts an arrangement of transverse inlet ducts and transverse drawoff ducts that is adapted to generate a flow of humid air through the volume of grain as it travels downwards through the germination tower

[0028] DETAILED DESCRIPTION OF THE INVENTION

[0029] A first aspect of the invention relates to a method of continuously germinating grain in a germination tower, said germination tower comprising: an inlet for steeped grain located in the top of the germination tower; an outlet for germinated grain located in the bottom of the germination tower; a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising a plurality of transverse inlet ducts that are positioned across the height and width of the germination chamber and a plurality of transverse draw-off ducts that are positioned across the height and width of the germination chamber; said method comprising: a) continuously feeding steeped grain via the inlet for steeped grain into the germination tower, said steeped grain having a moisture content of 28 to 48 wt.%; b) allowing the grains to move downwards in response to gravity through the germination chamber and to pass between the inlet ducts and the draw-off ducts while introducing humid air via the inlet ducts and withdrawing air via the draw-off ducts; c) continuously removing germinated grains from the outlet for germinated grains; wherein the residence time of the grains in the germination tower is 12-120 hours.

[0030] The term “grain” as used herein refers to cereal grains that are harvested for human consumption.

[0031] The term “steeping” as used herein refers to a procedure in which grains are covered with steep water to increase the moisture content of the grain (‘wet stand’). The wet stands may be interrupted by so called ‘dry stands’, during which the water is drained out and fresh air may be supplied to remove excess carbon dioxide.

[0032] The term “germinating” as used herein refers to the procedure in which a bed of steeped grains is allowed to germinate under humid conditions.

[0033] The term “chit” as used herein refers to the initial growth phase of the malt rootlets The term “malted” as used herein refers to grains that have germinated to the extent that they have formed a chit.

[0034] The term “malt” as used herein refers to malted cereal grain, such as malted barley.

[0035] The term “or” as used herein should be construed as “and / or”, unless specified otherwise.

[0036] The term “a” or “an” as used herein is defined as “at least one” unless specified otherwise.

[0037] Numerical ranges expressed in the format "from x to y" are understood to include x and y.

[0038] Whenever components A and B are said to be present in a weight ratio of x:y, what is meant is that the concentration of component A in wt.% divided by the concentration of component B in wt.% equals x:y.

[0039] Ratios mentioned herein are based on weight / weight, unless indicated otherwise. Similarly, all percentages are percentages by weight (w / w) unless otherwise indicated.

[0040] When multiple preferred ranges are described in the format "from x to y" for a specific feature, it should be understood that all ranges combining the different endpoints are also contemplated.

[0041] If, for a particular component, a range of 0% to y% or less than y% is recited, said ingredient may be absent.

[0042] The term "continuous", as used herein, refers to an operation that is carried out without interruption for at least 3 hours.

[0043] The transverse inlet ducts preferably are provided with one or more air exit openings. The transverse draw-off ducts preferably are provided with one or more air entry openings.

[0044] Preferably, the grain that is germinated in the present method is selected from barley, wheat, sorghum, rye and combinations thereof. More preferably, the grain is selected from barley, wheat and combinations thereof. Most preferably, the grain is barley The steeped grain is preferably continuously fed into the germination tower at a flow rate in the range of 0.5 to 12 MT / h, more preferably at a flow rate of 1 to 8 MT / h and most preferably at a flow rate of 1.5 to 6 MT / h.

[0045] In the present method, the grains move downwards through the germination chamber as a bed of grains. In a preferred embodiment, the grain passes through the germination tower at an vertical flow rate of 0.1-2 m / h, more preferably of 0.2-1.5 m / h, most preferably of 0.4-1.3 m / h.

[0046] Preferably, the steeped grain has a moisture content of 30-48 wt.%, more preferably of 32-46 wt.%, even more preferably of 33-45 wt.% as it enters into the germination tower.

[0047] The steeping of the grains may suitably be achieved in a continuous manner by transporting the grains through one or more screw conveyors (e.g. washing screws, sweeping augers) in which the grains are combined with steeping water to continuously produce the steeped grains. Resting time may be provided in between transportation stages by allowing the grains to absorb water in a tank or a tube.

[0048] The steeping water used for steeping the grains preferably has a temperature of 10-35°C, more preferably of 15-25 °C and most preferably of 18-20 °C.

[0049] Preferably, the total steeping time is at least 8 hours, more preferably 10-24 hours and most preferably 14-20 hours.

[0050] According to a particularly preferred embodiment, the germination chamber comprises two or more vertically arranged interconnected germination zones, each of said germination zones being provided with a plurality of transverse inlet ducts that are positioned across the height and width of each germination zone and a plurality of transverse draw-off ducts that are positioned across the height and width of each germination zone, wherein the introduction of humid air through the transverse inlet ducts is controlled separately for each germination zone. This arrangement offers the advantage that the germination conditions in each germination zone can adapted separately. Furthermore, this arrangement offers the advantage that residence time of the grain in the germination tower can be reduced by not using one or more of the upper germination zones. Preferably, for each germination zone flow rate, humidity and temperature of the humid air that is introduced in said germination zone is controlled separately. Thus, germination conditions in each germination zone can be controlled independently.

[0051] In a further preferred embodiment, the germination chamber comprises one or more stirring zones in which the downwards moving grains are stirred by a rotating stirrer. By stirring the grains as they move down through the germination chamber, it can be ensured that cohesion between grain particles, leading to so called bridging, is prevented. Preferably, the rotating stirrer employed rotates around a horizonal axis. The stirring zone preferably comprises a plurality of horizontally rotating stirrers that are arranged side by side. Preferably the germination chamber comprises 2-12, more preferably 3-8 stirring zones.

[0052] In a particularly preferred embodiment, the germination tower comprises at least 3, more preferably 3 to 10 and most preferably 4 to 8 of the vertically arranged interconnected germination zones.

[0053] The vertically arranged interconnected germination zones preferably each have a height of 0.5-4 m, more preferably of 0.7-3.5 m, even more preferably of 1.0-3.5 m, and most preferably of 1.5-2.5 m. Here the hight of a germination zone equals the vertical distance between the bottom of the lowest transverse duct and the top of the highest transverse duct, wherein each of said transverse ducts is one of the plurality of transverse inlet ducts or one of the plurality of transverse draw-off ducts.

[0054] The vertically arranged interconnected germination zones preferably each have an internal volume of 0.5-40 m3, more preferably of 1-30 m3and most preferably of 2-25 m3.

[0055] In the present method, the humid air that is introduced via the inlet ducts and that is withdrawn via the draw-off ducts passes through the grains as they travel downwards between those ducts. The resulting air flow serves to maintain optimum temperature, humidity, and oxygen and carbon dioxide levels for germination.

[0056] The humid air that is introduced via the inlet ducts preferably has a relative humidity of 60- 100%, more preferably 70-100%, even more preferably 80-100%, most preferably of 85- 100%.

[0057] The temperature of the humid air that is introduced via the inlet ducts preferably has a temperature of 12-40 °C, more preferably of 15-35 °C, most preferably of 18-30 °C. In a preferred embodiment, the air flows between the plurality of inlet ducts and draw-off ducts at a time-averaged flow rate of 100-1 ,000 m3 / MT / h, preferably 130-800 m3 / MT / h, more preferably 160-600 m3 / MT / h. Most preferably, the air flows between the plurality of inlet ducts and draw-off ducts at a time-averaged flow rate of 200-500 m3 / MT / h.

[0058] The present method of continuously germinating grain can be used to produce ordinary malt as well as chit malt. In accordance with one advantageous embodiment, the method is used to produce a chit malt by giving the grains a residence time in the germination tower of 12-48 hours, preferably of 18-36 hours.

[0059] According to another advantageous embodiment, the germination method is used to produce an amylolytic malt by giving the grains a residence time in the germination tower of 60-120 hours, preferably of 64-90 hours, more preferably of 68-80 hours.

[0060] Humidity of the grains within germination tower may also be controlled by spraying water onto the grains. Thus, in an embodiment of the present method water is sprayed onto the grains in the germination chamber.

[0061] The chitting rate refers to the percentage of grains that have germinated to the extent that they have formed a chit. It can be calculated using the following formula: 100 wherein CR is the chitting rate, Grainsc is the number of grains that have formed a chit and Grains? is the total number of grains.

[0062] In a preferred embodiment, the chitting rate of the germinated grain that is removed from the outlet for germinated grain is at least 80%, more preferably at least 85%, even more preferably at least 88%, and most preferably at least 90%.

[0063] The outlet through which the germinated grains are removed from the germination tower preferably comprises one or more outlet openings whose aperture is adjustable. By adjusting the aperture of the outlet openings, the flow rate and the height of the bed of grains within the germination chamber can be controlled. According to a preferred embodiment, the one or more adjustable openings are provided in the form of slits whose width can be adjusted.

[0064] The present method of continuously germinating grain is preferably carried out in a germination tower as described below. A second aspect of the invention relates to a germination tower for carrying out the method described above, said germination tower comprising:

[0065] • an inlet for steeped grain located in the top of the germination tower;

[0066] • an outlet for germinated grain located in the bottom of the germination tower;

[0067] • a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising (i) a plurality of transverse inlet ducts with one or more air exit openings that are positioned across the height and width of the germination chamber; and (ii) a plurality of transverse draw-off ducts with one or more air entry openings that are positioned across the height and width of the germination chamber;

[0068] • an air pump for generating an air flow from the plurality of transverse inlet ducts to the plurality of transverse draw-off ducts, said air pump being position upstream of the transverse inlet ducts or downstream of the transverse draw-off ducts;

[0069] • an air humidifier that is positioned upstream of the transverse inlet ducts.

[0070] According to a particularly preferred embodiment, the germination tower comprise a heat exchanger unit for heating and / or cooling air that is located upstream of the transverse inlets.

[0071] The germination chamber preferably comprises two or more vertically arranged interconnected germination zones, each of said germination zones being provided with a plurality of transverse inlet ducts that are positioned across the height and width of each germination zone and a plurality of transverse draw-off ducts that are positioned across the height and width of each germination zone, wherein the introduction of humid air through the transverse inlet ducts can be controlled separately for each germination zone.

[0072] According to a preferred embodiment, the plurality of transverse inlets of each germination zone is connected to an air inlet chamber that is located downstream of the air humidifier. More preferably, each germination zone is connected to a different air inlet chamber. According to a particularly preferred embodiment, flow rate, humidity and temperature of the air that is provided to the different air inlet chambers can be controlled separately. Thus, germination conditions in each germination zone can be controlled separately.

[0073] The germination chamber preferably comprises one or more stirring zones in which the downwards moving grains are stirred by a rotating stirrer. By stirring the grains as they move down through the germination chamber, it can be ensured that cohesion between grain particles, leading to so called bridging, is prevented. Preferably, the rotating stirrer employed rotates around a horizonal axis. The stirring zone preferably comprises a plurality of horizontally rotating stirrers that are arranged side by side. Preferably the germination chamber comprises 2-12, more preferably 3-8 stirring zones.

[0074] In a particularly preferred embodiment, the germination tower comprises at least 3, more preferably 3 to 10 and most preferably 4 to 8 of the vertically arranged interconnected germination zones.

[0075] The vertically arranged interconnected germination zones preferably each have a height of 0.5-4 m, more preferably of 0.7-3.5 m, even more preferably of 1.0-3.5 m, and most preferably of 1.5-2.5 m. Here the hight of a germination zone equals the vertical distance between the bottom of the lowest transverse duct and the top of the highest transverse duct, wherein each of said transverse ducts is one of the plurality of transverse inlet ducts or one of the plurality of transverse draw-off ducts.

[0076] The vertically arranged interconnected germination zones preferably each have an internal volume of 1-80 m3, more preferably of 3-40 m3and most preferably of 8-25 m3.

[0077] In accordance with a particularly preferred embodiment, the total number of inlet ducts equals the total number of draw-off ducts.

[0078] The top of said inlet ducts and the top of the draw-off ducts is preferably shaped as a gable roof. By shaping the ducts in this way, a steady flow of grains without clogging can be realised.

[0079] Preferably, the inlet ducts and draw-off ducts have a height between 5-50 cm, preferably 8-30 cm, more preferably 10-25 cm, most preferably, the inlets ducts and draw-off ducts have a height between 12-20 cm.

[0080] The inlet ducts and draw-off ducts preferably have a width between 5-50 cm, preferably 8-30 cm, more preferably 10-25 cm, most preferably, the inlets ducts and draw-off ducts have a width between 12-20 cm.

[0081] According to a particularly preferred embodiment, the germination chamber comprise a first vertical sidewall and a second vertical sidewall opposite the first vertical sidewall; wherein the plurality of transverse inlet ducts extend between the first vertical sidewall and the second vertical sidewall, said inlet ducts including a first end at the first vertical sidewall that is open to form an entry end and an opposite second end at the second vertical sidewall that is blocked to form a blocked end; wherein the plurality of transverse draw-off ducts extend between the first vertical sidewall and the second vertical sidewall, said draw-off ducts including a first end at the first vertical sidewall that is blocked to form a blocked end and an opposite second end at the second vertical sidewall that is open to form an exit end; wherein humid air from the air humidifier can flow into the open entry ends at the first end of the plurality of ducts and flow out of the open exit ends of the ducts.

[0082] In a particularly preferred embodiment, the inlet ducts and draw-off ducts are arranged horizontally. Alternatively, said inlet ducts and draw-off ducts may be arranged at an angle relative to a horizontal plane of not more than 20°, preferably not more than 15°, more preferably not more than 10°, most preferably not more than 5°.

[0083] Preferably, the plurality of transverse inlet ducts is in parallel-spaced alignment in a horizontal plane with one another. Furthermore, the plurality of transverse draw-off ducts is also in parallel-spaced alignment in a horizontal plane with one another.

[0084] To ensure that the humid air travels optimally through the grain bed, the rows of transverse inlet ducts and rows of transverse draw-off ducts are preferably alternatingly vertically stacked.

[0085] The vertically stacked rows of transverse inlet ducts and transverse draw-off ducts are preferably positioned in an alternating staggered alignment such that the ducts of a horizontal row are offset from adjacent ducts above and below.

[0086] To optimize space usage within the germination chamber, the inlet- and draw-off ducts are preferably arranged in a close-packed array structure, wherein the shortest air travel distance between the transverse inlet ducts and the transverse draw-off duct is 5-50 cm, more preferably 8-45 cm, even more preferably 10-40 cm, and most preferably 15-35 cm.

[0087] To allow humid air to enter the germination chamber via the inlet ducts, said inlet ducts have one or more openings. Preferably, said one or more openings are located in the underside of the inlet ducts.

[0088] In a preferred embodiment, the combined surface area of the one or more openings in the underside of the inlet ducts represents 20-100%, more preferably 40-100%, even more preferably 60-100%, and most preferably 80-100% of the horizontal cross-sectional surface area of the inlet ducts.

[0089] To allow air to exit the germination chamber via the draw-off ducts, said draw-off ducts have one or more openings. In a preferred embodiment, said openings are located in the underside of the draw-off ducts.

[0090] In a preferred embodiment, the combined surface area of the one or more openings in the underside of the draw-off ducts represents 20-100%, more preferably 40-100%, even more preferably 60-100%, and most preferably 80-100% of the horizontal cross-sectional surface area of the draw-off ducts.

[0091] The air pump for generating an air flow from the plurality of transverse inlet ducts to the plurality of transverse draw-off ducts preferably is a ventilator.

[0092] The air pump is preferably located downstream of the transverse draw-off ducts.

[0093] In a particularly preferred embodiment, the inlet ducts and draw-off ducts are made of a non- corrosive material, preferably a non-corrosive material selected from aluminium or stainless steel.

[0094] In a preferred embodiment of the germination tower, the in the top of the germination chamber means for spraying water onto the grain bed are provided.

[0095] The inlet for steeped grain of the germination tower is preferably connected to a washing screw that is adapted for the continuous steeping of grains.

[0096] In order to prevent clogging, the germination chamber is preferably provided with one or more vibration units that are capable of causing vibration of the walls of the germination chamber, the plurality of transverse inlet ducts and the plurality of transverse draw-off ducts.

[0097] The outlet for germinated grain located in the bottom of the germination tower preferably comprises one or more outlet openings whose aperture is adjustable. According to a preferred embodiment, the one or more adjustable openings are provided in the form of slits whose width can be adjusted. In a preferred embodiment, the maximum volume of grain that can be held by the germination tower is between 10-300 m3, more preferably between 20-200 m3, and most preferably between 30-150 m3.

[0098] Figure 1 shows a germination tower 1 according to the present invention. Steeped grains 2 are continuously introduced at a constant flow rate via inlet 3 into the top of the germination chamber 4 to maintain a volume of grain 5, while germinated grains 6 are continuously exiting the germination tower 1 via outlets 7 at a flow rate that ensures that the volume of the grain 5 within the germination chamber 4 remains constant.

[0099] The germination chamber 4 comprises four germination zones 8. Each germination zone 8 is separately provided with humid air 9 via inlet chambers 10. The inlet chambers 10 are separated by separating walls 11. The humid air 9 enters the germination zones 8 via a plurality of transverse inlet ducts 12. The humid air 9 travels from the transverse inlet ducts 12 through the volume of grain 5 to the transverse outlet ducts 13 and leaves each of the germination zones 8 via an outlet chamber 14. The outlet chambers are separated by separating walls 15. Each germination zone 8 has its own inlet chamber 10 and outlet chamber 14, enabling the flow rate within each germination zone 8 to be controlled separately. The air leaves the outlet chambers 14 via outlets 16 and is collected and vented via air vent 17.

[0100] Each germination zone comprises one or more stirring zones (not shown). Each stirring zone comprises a plurality of horizontally rotating stirrers (not shown).

[0101] As the grains travel from the top of the volume of grain 5 to the outlet 7, the passage of humid air 9 through the volume of grain 5 promotes germination of the grains while the stirrers 15 ensure that plug flow conditions are maintained. After having exited the germination chamber 4 through outlets 7, the germinated grains 6 may be transported by, for instance, a conveyor belt or a screw conveyor to the next process step.

[0102] Figure 2 shows in more detail how the humid air 9 travels from the transverse inlet ducts 12 through the volume of grain 5 to the transverse outlet ducts 13.

[0103] EXAMPLES

[0104] Example 1

[0105] Barley was germinated in a germination tower in accordance with the present invention. The germination tower contained 4 equally sized germination chambers that were each independently provided with a continuous flow of humid air. Each germination chamber contained 24 transverse inlet ducts and 24 transverse draw-off ducts. Both type of ducts were shaped as gable roofs so air could exit and enter via the bottom of the ducts. The shortest air travel distance between the transverse inlet ducts and the transverse draw-off ducts was 40 cm. Horizontally rotating stirrers were provided between each of the germination chambers.

[0106] Steeped barley grains having a water content of approximately 32 wt.% were continuously fed into the top of the germination tower. Humid air having a temperature of 20°C and a relative humidity of between 40 to 60% was continuously introduced via the transverse inlet duct into the germination chambers while the steeped barley grains slowly moved downward between the transverse ducts. Total air flow was approximately 250 m3 / MT / h The water content of the germinating grains was maintained at approximately 32 wt.% during passage through the germination tower. After a residence time in the germination tower of 24 hours, a green malt with a chitting rate of 97% was obtained.

[0107] The green malt leaving the germination tower was continuously transferred into a belt dryer in which the malt was dried to produce a chit malt.

[0108] The chit malt was analysed. The results of the analyses are shown in Table 1.

[0109] Table 1

[0110] Example 2

[0111] Barley was germinated in the same way as in Example 1 , except that this time the flow rate of the steeped grains was reduced to increase the residence time in the germination tower to 72 hours. The malt so obtained had considerable amylolytic activity as is evident from the data presented in Table 2.

[0112] Table 2

Claims

CLAIMS1 . A method of continuously germinating grain in a germination tower, said germination tower comprising: an inlet for steeped grain located in the top of the germination tower; an outlet for germinated grain located in the bottom of the germination tower; a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising a plurality of transverse inlet ducts with one or more air exit openings that are positioned across the height and width of the germination chamber and a plurality of transverse draw-off ducts with one or more air entry openings that are positioned across the height and width of the germination chamber; said method comprising: a) continuously feeding steeped grain via the inlet for steeped grain into the germination tower, said steeped grain having a moisture content of 28 to 48 wt.%; b) allowing the grains to move downwards in response to gravity through the germination chamber and to pass between the inlet ducts and the draw-off ducts while introducing humid air via the inlet ducts and withdrawing air via the draw-off ducts; c) continuously removing germinated grains from the outlet for germinated grains; wherein the residence time of the grains in the germination tower is 12-120 hours.

2. Method according to claim 1 , wherein the method comprises continuously steeping of grain in a screw conveyor to produce the steeped grain.

3. Method according to claims 1 or 2, wherein the germination chamber comprises two or more vertically arranged interconnected germination zones, each of said germination zones being provided with a plurality of transverse inlet ducts that are positioned across the height and width of each germination zone and a plurality of transverse draw-off ducts that are positioned across the height and width of each germination zone, wherein the introduction of humid air through the transverse inlet ducts is controlled separately for each germination zone.

4. Method according to any one of the preceding claims, wherein the germination chamber comprises one or more stirring zones in which the downwards moving grains are stirred by a rotating stirrer.

5. Method according to any one of the preceding claims, wherein the time averaged flow rate between the plurality of inlet ducts and draw-off ducts is 100-1 ,000 m3 / MT / h.

6. Method according to any one of the preceding claims, wherein the humid air that is introduced via the inlet ducts has a temperature between 12 and 40 °C.

7. Method according to any one of the preceding claims, wherein the humid air that enters the germination chamber through the inlet ducts has a relative humidity of 60% - 100%.

8. Method according to any one of the preceding claims, wherein the grain passes through the germination tower at an vertical flow rate of 0.1-2 m / h.

9. A germination tower for carrying out the method according to any one of the preceding claims, said germination tower comprising:• an inlet for steeped grain located in the top of the germination tower;• an outlet for germinated grain located in the bottom of the germination tower;• a germination chamber that is located between the inlet for steeped grain and the outlet for germinated grain, said germination chamber comprising (i) a plurality of transverse inlet ducts with one or more air exit openings that are positioned across the height and width of the germination chamber; and (ii) a plurality of transverse draw-off ducts with one or more air entry openings that are positioned across the height and width of the germination chamber;• an air pump for generating an air flow from the plurality of transverse inlet ducts to the plurality of transverse draw-off ducts, said air pump being position upstream of the transverse inlet ducts or downstream of the transverse draw-off ducts ;• an air humidifier that is positioned upstream of the transverse inlet ducts.

10. The germination tower according to claim 9, wherein the germination chamber comprises a first vertical sidewall and a second vertical sidewall opposite the first vertical sidewall; wherein the plurality of transverse inlet ducts extend between the first vertical sidewall and the second vertical sidewall, said inlet ducts including a first end at the first vertical sidewall that is open to form an entry end and an opposite second end at the second vertical sidewall that is blocked to form a blocked end; wherein the plurality of transverse draw-off ducts extend between the first vertical sidewall and the second vertical sidewall, said draw-off ducts including a first end at the first vertical sidewall that is blocked to form a blocked end and an opposite second end at the second vertical sidewall that is open to form an exit end;wherein humid air from the air humidifier can flows into the open entry ends at the first end of the plurality of ducts and flow out the open exit ends of the ducts.11 . The germination tower according to claim 10, wherein the entry ends of the transverse inlet ducts are connected to an air inlet chamber that is located downstream of the air humidifier.

12. The germination tower according to claim 10 or 11 , wherein the top of the inlet ducts and the top of the draw-off ducts is shaped as a gable roof.

13. The germination tower according to any one of claims 10-12, wherein the plurality of transverse inlet ducts are in parallel spaced alignment in a horizontal plane with one another; wherein the plurality of transverse draw-off ducts in parallel spaced alignment in a horizontal plane with one another, and wherein the rows of transverse inlet ducts and rows of transverse draw-off ducts are alternatingly vertically stacked.

14. The germination tower according to claim 13, wherein the alternatingly vertically stacked rows of transverse inlet ducts and transverse draw-off ducts are positioned in an alternating staggered alignment such that duct of a horizontal row is offset from adjacent ducts above and below it.

15. The germination tower according to any one of claims 10-14, wherein the shortest air travel distance between the transverse inlet ducts and the transverse draw-off ducts is between 5 cm and 50 cm.