WO1986006740A1

WO1986006740A1 - Malting

Info

Publication number: WO1986006740A1
Application number: PCT/GB1986/000235
Authority: WO
Inventors: Alan Aldred Pool; James Richard Allan Pollock
Original assignee: Pollock And Pool Limited
Priority date: 1985-05-03
Filing date: 1986-05-02
Publication date: 1986-11-20
Also published as: FI870011A; EP0220261A1; DK1987D0; ES554637A0; FI870011A0; AU5866486A; GB8511342D0; HUT44284A; DK1987A; ES8801367A1

Abstract

A method of malting comprising: steeping cereal grain subsequently subjecting the grain to treatment without damaging its germinative ability, the moisture content of the steeped grain being insufficient to allow, if the grain were subsequently stored in the presence of air at 16oC for 5 days, a growth of roots and/or rootlets having a total dry weight greater than 0.5% of the dry weight of the grain before such storage; exposing the grain to air to convert the grain to moist malt; characterised in that: the treatment of the grain is such as to provide an elastic deformation of the individual grains and is such that the width of the individual grains increases by at least 5% and if the grain is left without further treatment for 24 hours said width is then no more than 2% greater than said width immediately before said treatment providing elastic deformation.

Description

MALTING

The present invention relates to malting.

British patent no. 1476082 discloses a method of malting comprising: submitting grain to treatment, such as by passing the grain between rollers, to rupture the surface of the grain, without damaging the germinative ability of the grain, the surface rupturing treatment being such that substantial rootlet growth would occur if the moisture content of the treated grain were raised to 46% by weight and then the grain were kept in air at 16°C for 5 days, and steeping the grain, the moisture content of the steeped and treated grain being insufficient to allow a growth of roots having a dry weight greater than 0.5% of the dry weight of the grain if the grain were subsequently stored in the presence of air at 16°C for 5 days; treating the grain with gibberellic acid; exposing the grain to humid air to convert the grain into moist malt; and drying the malt. As compared with conventional malting, this method reduces the amount of water with which the grain is steeped thereby reducing the amount of water it is necessary to evaporate in drying the malt.

It has now been discovered that by selecting conditions under which the grain is treated so as to provide an elastic deformation of the individual grains preferably with substantially no rupturing of their surface occurring and optionally by omitting the treatment of the grain with gibberellic acid there may be obtained improved or otherwise desirable results differing from the results obtained by the method disclosed in the aforementioned British patent.

In accordance with the present invention, there is provided a method of malting, comprising: steeping cereal grain, such as barley, and subsequently submitting the grain to treatment, such as by passing the grain between rollers, without damaging the germinative ability of the grain, the moisture content of the steeped grain being insufficient to allow, if the grain were subsequently stored in the presence of air at 16°C for 5 days, a growth of roots and/or rootlets having a total dry weight greater than 0.5% of the dry weight of the grain before such storage; exposing the grain to air, preferably moist or humid air, to convert the grain to moist malt; and optionally drying the moist malt; characterised in that: the treatment of the grain is such as to provide elastic deformation of the individual grains is such that the width of the individual grains increases by at least 5% and is such that if the grain is left without further treatment for 24 hours said width is then no more than 2% greater than said width immediately before said treatment to provide the elastic deformation.

The husk of the grain is not substantially removed by the treatment of the grain providing the elastic deforrration.

It is desirable that substantially no rupturing of the surfaces of the individual grains is caused by the treatment of the grain to provide the elastic deformation.

The grain may be malted directly after the treatment to provide the elastic deformation (i.e. without treatment with gibberellic acid).

Alternatively the grain may be treated with gibberellic acidpreferably before being exposed to the air to convert it to malt and preferably after said treatment providing the elastic deformation. The amount of gibberellic acid preferably does not exceed 1.0 part by weight, and more preferably does not exceed 0.5 parts by weight, per million parts by weight of the dry weight of the grain. The rollers preferably have a diameter of at least 40 cm.

Preferably the rollers rotate at exactly the same circumferential speed and, at the nip between the rollers through which the grain passes, both move circumferentially in the same direction as the grain.

Preferably the grain is steeped to a moisture content not exceeding 40% by weight based on the dry freight of the grain.

Preferably the treatment of the grain to provide the elastic deformation is such that substantial root and/or rootlet growth would occur if the moisture content of the grain were, after said treatment and before exposure of the grain to the air, raised to 46% by weight based on the dry weight of the grain and the grain were then kept in air at 16°C for 5 days.

Apparatus suitable for carrying out the method of the invention is shown diagrammatically in the accompanying drawing.

Referring to the drawing, grain 1 is supplied to a feed hopper 2. The grain 1 discharges from the hopper 2 and is fed by a vibratory feed tray 3 to a mill inlet hopper 4. The grain discharges from the hopper 4 into a nip 5 defined between rolls 6 against which scrapers 7 bear. The rolls 6 have a diameter greater than 40 cm. The rolls 6 rotate at exactly the same circumferential speed and, as the nip 5, move circumferentially downwardly. The grain 1 passes downwardly through the nip 5 and into a mill outlet hopper 8 from which the grain discharges onto a conveyor 9.

The invention is illustrated by the following examples.

Examples

Various barleys (A, B, C, D and E) were steeped to moisture contents between 37 and 38%. Small quantities of the steeped grain were kept in air at 16°C for 5 days, after which it was confirmed that in no case did the total dry weight of roots and rootlets produced exceed 0.5%. The remainder of the steeped grain was squeezed by being passed between rollers adjusted so that the average widths of the individual grains immediately after squeezing was 105% or more of the average widths of the steeped grains prior to the squeezing, the increase in width being elastic so that after 24 hours the grains had largely regained their original shapes and it was observed that substantially no rupturing of the surfaces of the individual grains had occurred. After the steeped grain had been passed between the rollers, the πoisture content of small quantities of the grain was raised to 46% by weight based on the dry weight of the grain and these small quantities were kept in air at 16°C for 5 days. Substantial growth of roots and/or rootlets occurred showing that the passage of the steeped grain between the rollers had not damaged the germinative ability of the grain. The squeezed grain was either malted in moist or humid air without addition of gibberellic acid or malted after gibberellic acid in water had been sprayed on the grain. The resulting malts were dried in a kiln, the yield of malt was found and the malt was analysed. The observations made are summarised in the table below.

In each case, malt of good quality was obtained. The addition of gibberellic acid allowed adjustment to be made of some of the analyses of the malts, notably of soluble nitrogen and of viscosity of wort produced from the malts, in a way similar to the effect of this substance in conventional malting. While the main analyses made were such as to show that the malts wsre satisfactory material for making beers, two of the malts were analysed for the yield which might be expected from them in the distilling industry, with results showing that they would also be useful for making whisky or similar products.

Claims

1. A method of malting comprising:

steeping cereal grain and subsequently subjecting the grain to treatment without damaging its germinative ability, the moisture content of the steeped grain being insufficient to allow, if the grain were subsequently stored in the presence of air at 16°C for 5 days, a growth of roots and/or rootlets having a total dry weight greater (than 0.5% of the dry weight of the grain before such storage; exposing the grain to air to convert the grain to moist malt;

characterised in that:

the treatment of the grain is such as to provide an elastic deformation of the individual grains and is such that the width of the individual grains increases by at least 5% and if the grain is left without further treatment for 24 hours said width is then no more than 2% greater than said width immediately before said treatment providing elastic deformation.

2. A method according to claim 1, wherein the grain is not treated with gibberellic acid.

3. A method according to claim 1, wherein the grain, before being exposed to air to convert it to malt, is treated with gibberellic acid.

4. A method according to claim 3, wherein the grain is treated with the gibberellic acid after said treatment providing the elastic deformation.

5. A method according to claim 3 or 4, wherein the amount of gibberellic acid does not exceed 1.0 part by weight per million parts of the dry weight of the grain.

6. A method according to claim 5, wherein the amount of gibberellic acid does not exceed 0.5 parts by weight per million parts of the dry weight of the grain.

7. A method according to any preceding claim, wherein the air to which the grain is exposed to convert it to malt is humid or moist air.

8. A method according to any preceding claim, wherein said treatment providing elastic deformation comprises passing the grain between rollers.

9. A method according to claim 8, wherein the rollers have a minimum diameter of 40 cm.

10 A method according to claim 8 or 9,, wherein the rollers rotate at exactly the same circumferential speed (and, at the nip between the rollers through which the grain passes, move circumferentially in the same direction as the grain).

11. A method according to any preceding claim, wherein the grain is barley.

12. A method according to any preceding claim, wherein the grain is steeped to a moisture content not exceeding 40 per cent by weight based on the dry weight of the grain.

13. A method according to any preceding claim, wherein the treatment of the grain to provide elastic deformation is such that substantial root and/or rootlet growth would occur if the moisture content of the grain were then raised to 46 per cent by weight and then the grain was kept in air at 16°C for 5 days.

14. A method according to any preceding claim, further comprising drying the moist malt.

15. A method according to any preceding claim, wherein substantially no rupturing of the surface of the individual grains results frαn the treatment to provide the elastic deformation.