GB2316951A

GB2316951A - A process for producing whisky

Info

Publication number: GB2316951A
Application number: GB9618174A
Authority: GB
Inventors: James Little Beveridge; Neil Graham Cocharane; Douglas Hay; Alison Mary Lynn Mcdonald; Steve Mcgingle; Janet Mary Thornton
Original assignee: United Distillers PLC
Current assignee: United Distillers PLC
Priority date: 1996-08-30
Filing date: 1996-08-30
Publication date: 1998-03-11
Anticipated expiration: 2016-08-30
Also published as: GB9618174D0; GB2316951B

Abstract

The process comprises the steps of:- (i) forming a mixture comprising milled malt and water at a temperature in the range of from 14 to 26{C; (ii) adding yeast to the mixture from step (i) and allowing the resulting mixture to ferment; and (iii) distilling the fermented mixture from step (ii).

Description

A Process for Producinq Whisky The present invention relates to a process for producing whisky and, in particular, to a process for producing malt whisky.

Malt whisky is produced by fermenting a mash of malted barley and water with yeast.

In its simplest terms, conventional malt whisky production can be divided into five main processing steps. The first step, known as malting, involves adding water to barley to initiate germination. The germinated barley is cleaned and then dried in a kiln.

The dried malt is subsequently milled to form a malt flour called grist. In the second step, known as mashing, the grist is added to water at a temperature typically in the region of 60 to 700C and the mixture, called mash, stirred for several hours. The mash is then filtered resulting in a sweet liquid called wort and a residue which comprises husks and spent grains.

In the third step, the wort is cooled to a temperature in the region of 20 to 250C and conveyed to a fermentation vessel called a washback. Yeast is then added to the wort and fermentation commences resulting in an alcoholic liquid called wash. The wash is then distilled in the fourth step, whereby the alcohol in the wash is separated from the water. Finally, in the fifth step, known as maturation, the whisky is stored in oak barrels.

We have now developed a process which results in an increased spirit yield compared with the conventional processes and which produces a whisky with a distinctive character.

Accordingly, in a first aspect the present invention provides a process for the production of whisky comprising the steps of: (i) forming a mixture comprising milled malt and water at a temperature in the range of from 14 to 260C; (ii) adding yeast to the mixture from step (i) and allowing the resulting mixture to ferment; and (iii)distilling the fermented mixture from step (ii) In contrast to the conventional procedure, the mixture from step (i) is not separated into wort and a residue of husks and spent grains before the yeast is added. The mixture of step (i) is not mashed.

Preferably the temperature at which the mixture of step (i) is formed is in the range of from 16 to 240C, more preferably from 18 to 220C, still more preferably approximately 200C. It will be appreciated by those skilled in the art that a separate cooling mechanism would be required if the temperature exceeded approximately 24 cm.

In order to control excessive bacterial infection, which would result in a reduced spirit yield, the yeast is preferably added to the mixture from step (i) within 1 hour of forming the said mixture, more preferably within 30 minutes, still more preferably within 15 minutes, still more preferably within 5 minutes.

Advantageously the yeast is added to the mixture from step (i) by conveying the mixture from step (i) concurrently with the yeast into a fermentation vessel.

The resulting mixture from step (ii) is preferably allowed to ferment adiabatically.

Fermentation continues for a period of time typically in the range of from 40 to 100 hours.

In another aspect, the present invention provides a process for the production of whisky comprising the steps of: (a) forming a mixture comprising milled malt and water at a temperature in the range of from 14 to 260C; (b) forming a mixture comprising milled malt and water at a temperature in the range of from 60 to 70 C; (c) cooling the second mixture to a temperature in the range of from 14 to 260C; (d) forming a mixture comprising yeast, the mixture from step (a) and the mixture from step (c) and allowing the resulting mixture to ferment; and (e) distilling the fermented mixture from step (d).

Preferably the temperature at which the mixture of step (a) is formed and/or the temperature of step (c) is in the range of from 16 to 240C, more preferably from 18 to 220C, still more preferably approximately 20 CC.

In step (b), the mixture is preferably at a temperature in the range of from 63 to 650C and is preferably mixed for about 1 hour.

The mixture of step (d) is preferably obtained by first combining the mixture from step (a) and the mixture from step (c), followed by adding the yeast.

The mixture from step (a) may be combined with the mixture from step (c) by conveying the said mixtures concurrently into a fermentation vessel. The yeast is preferably added to the mixtures from step (a) and (c) within 1 hour, more preferably within 30 minutes, still more preferably within 15 minutes, still more preferably within 5 minutes.

Alternatively, the mixture of step (d) may be obtained by first adding the yeast to the mixture from step (c) followed by adding the mixture from step (a) to the mixture from step (c) and yeast. In this case, the mixture from step (a) is preferably added within 1 hour of adding the yeast, more preferably within 30 minutes, still more preferably within 15 minutes, still more preferably within 5 minutes. Advantageously the mixture from step (a) is added to the mixture from step (c) and yeast by conveying the mixture from step (a) concurrently with the mixture from step (c) and yeast into a fermentation vessel.

In an alternative embodiment of the second aspect of the present invention, the mixture of step (d) may be obtained by conveying, as three separate streams, the mixture from step (a), the mixture from step (c) and the yeast concurrently into a fermentation vessel.

Preferably the resulting mixture from step (d) is allowed to ferment adiabatically. Fermentation continues for a period of time typically in the range of from 40 to 100 hours.

In both aspects of the present invention the milled malt may be obtained from malt which has been dried by any of the conventional processes, such as direct or indirect fired malt kiln drying.

The milled malt may be obtained from any of the known barley varieties, such as Puffin, Derkado, Delibes or Maresi or a mixture of two or more thereof.

For higher spirit yields, the malt may be milled to give a fine particle size. For example, a typical particle size distribution would comprise in the range of from 0 to 20% coarse material and husk, in the range of from 65 to 75% fine grit and in the range of from 7 to 35% flour, preferably less than about 1% of coarse material and husk, about 68% fine grit and about 32% flour. Coarse material and husk is defined as material which is retained by a screen of 25 apertures/cm2; fine grit is defined as material which passes through a screen of 25 apertures/cm2 and is retained by screen of 800 apertures/cm2; and flour is defined as material which passes through a screen of 800 apertures/cm2.

It will be appreciated that in both aspects of the present invention, the mixture which is initially distilled will contain husks and spent grains.

Accordingly, two or more distillations are advantageously utilised.

After distillation, the thus formed spirit may be matured by the maturation procedures conventional in the art.

The present invention will now be further described with reference to the following examples.

Examples 1, 3 to 7 and 9 relate to the first aspect of the present invention and Example 2, 8 and 10 are comparative examples. Examples 11 and 13 relate to the second aspect of the present invention and Examples 12 and 14 are comparative examples.

Example 1 This Example relates to the process of the first aspect of the present invention carried out on an industrial scale. Approximately 7.6 tonnes of malt of barley variety Derkado was ground on a Porteous 4 roll mill to give a grist analysis of 13:66:22 (coarse material and husk:fine grit:flour). The grist was then mixed with water at approximately 20"C using a standard distillery mashing machine. Yeast was added to the mixture at a rate of approximately 6.1 g pressed yeast (Quest 'M yeast) per litre of wort.

The mixture was pumped to a distillery fermentation vessel and allowed to ferment adiabatically for approximately 70 hours. The fermented mixture was distilled using a standard malt distillery process resulting in a yield of 434 litres of alcohol per tonne of malt (at 100% dry matter).

Example 2 (comParative) For comparison, using a conventional procedure for malt whisky production, the same malt as used in Example 1 was ground on the same mill to give a grist analysis of 15:75:11. The grist was then mashed at approximately 63-64"C by a standard three water process to give a clear wort. The wort was cooled to approximately 20"C and transferred to a fermentation vessel where it was mixed with approximately 3.5 g pressed yeast (Quest M yeast) per litre of wort.

The mixture was allowed to ferment adiabatically for approximately 70 hours and was then distilled using a standard malt distillery process resulting in a yield of 417 litres of alcohol per tonne of malt (at 100% dry matter).

Example 3 This example relates to the process of the first aspect of the present invention carried out on a laboratory scale. Approximately 50 g of malt of barley variety Derkado was ground on a Miag mill at setting 14 to give a grist analysis of 19:73:8, and mixed with water at approximately 16 C. After approximately 1 hour at this temperature, the mixture was transferred to an insulated fermentation vessel and yeast was added to the mixture at a rate of approximately 10 g pressed yeast ("Quest M yeast) per litre wort. The mixture was allowed to ferment adiabatically for approximately 65 hours and the fermented mixture was then distilled resulting in a yield of 424 litres of alcohol per tonne of malt (at 100% dry matter).

Example 4 Using the same process as described in Example 3, but with a mashing temperature of approximately 20"C, the same malt gave a yield of 426 litres of alcohol per tonne of malt (at 100% dry matter).

Example 5 Using the same process as described in Example 3, but with a mashing temperature of approximately 240C, the same malt gave a yield of 424 litres of alcohol per tonne of malt (at 100% dry matter).

Example 6 This example relates to the process of the first aspect of the present invention carried out on a laboratory scale. Malt of barley variety Puffin, which had been dried by a direct fired malt kiln, was ground on a Miag mill at setting 2, and mixed with water at approximately 200C. After approximately 1 hour at this temperature, the mixture was transferred to an insulated fermentation vessel and yeast added at a rate of approximately 1.2 g dried yeast ("Quest "M" yeast) per litre wort. The mixture and yeast was then allowed to ferment adiabatically for approximately 65 hours. The fermented mixture was then distilled resulting in a yield of 445 litres of alcohol per tonne of malt (at 100% dry matter).

Example 7 Using the same process as described in Example 6, malt was prepared from the same malting batch but was dried in an indirect fired malt kiln. This resulted in a yield of 444 litres of alcohol per tonne of malt (at 100% dry matter).

Example 8 (comparative) The same Puffin malt as described in Example 6 was dried by a direct malt kiln and then mashed by a laboratory procedure corresponding to a conventional procedure for the production of malt whisky. The fermented mixture was then distilled which resulted in an alcohol yield of 415 litres of alcohol per tonne of malt (at 100% dry matter).

Example 9 This example relates to the process of the first aspect of the present invention carried out on a laboratory scale. Four barley varieties were individually ground on a Miag mill at setting 2, to give a grist analysis of, for example, in the case of Derkado malt (see table below) 0.05:67:33. Each of the ground varieties was then individually mixed with water at approximately 20"C. After approximately 1 hour at 200C, each mixture was transferred to an insulated fermentation vessel and yeast was added to the individual mixtures at a rate of approximately 1.2 g dried yeast ('Quest M yeast) per litre wort. The mixtures were then allowed to ferment adiabatically for approximately 65 hours. Each fermented mixture was then distilled and the alcohol yield assessed.

The alcohol yields were as follows: Malt of Barley Variety Alcohol litre/tonne malt (100% Dry matter) Puffin 446 Derkado 459 Delibes 452 Maresi 434 Example 10 (comParative) The same four malts as described in Example 9, were each individually mashed by a laboratory procedure corresponding to a conventional procedure for the production of malt whisky. The four mixtures were than fermented and distilled and the alcohol yields assessed. The alcohol yields were as follows: Malt of Barley Variety Alcohol litre/tonne malt (100% Dry matter) Puffin 417 Derkado 427 Delibes 415 Maresi 401 Example 11 This example relates to the process of the second aspect of the present invention carried out on a laboratory scale. Approximately 50 g of malt of barley variety Maresi was ground on a Miag mill at setting 2.

A first mixture was prepared by mixing a proportion (80%, 50% and 20%) of this grist with water at approximately 650C and holding and mashing the mixture (no wort separation however) at this temperature for approximately 1 hour, after which the mixture was cooled to approximately 200C. A second mixture was prepared by mixing the balance of the grist (20%, 50% and 80%) with water at approximately 20"C. Next, a fermentation mixture was prepared by combining the cooled first mixture with the second mixture, transferring the resulting mixture to an insulated fermentation vessel, adding yeast at a rate of approximately 1.2 g dried yeast (Quest 'M' yeast) per litre of final wort, and allowing the mixture to ferment adiabatically for approximately 65 hours.

Each fermentation was distilled and the alcohol yields obtained were as follows: % grist mashed % grist added to Alcohol fermentation (0 hrs) litre/tonne malt (100% Dry matter) 80 20 429 50 50 432 20 80 434 Example 12 (comparative) For comparison purposes, 100% of the grist of Example 11 was mixed with water at approximately 65CC and the procedure of Example 11 repeated giving the following result.

% grist mashed * grist added to Alcohol fermentation (0 hrs) litre/tonne malt (100% Dry matter) 100 0 418 Example 13 Using an identical procedure to that described in Example 11, the balance of the grist was added to the fermentation mixture 21 hours after the addition of the yeast. The alcohol yields were as follows: z grist mashed % grist added to Alcohol fermentation (21 hrs) litre/tonne malt (100 Dry matter) 80 20 422 50 50 417 20 80 396 Example 14 (comparative) For comparison purposes, 100% of the grist of Example 13 was mixed with water at approximately 65"C and the procedure of Example 13 repeated giving the following result.

% grist mashed % grist added to Alcohol fermentation (0 hrs) litre/tonne malt (100% Dry matter) 100 0 415 The present invention provides a process for the production of malt whisky in which the spirit yield is typically improved by 4 to 9% compared with conventional processes and less starch and sugars remain at the end of fermentation step. The resulting spirit has a distinctive and characteristic organoleptic character. Samples produced according to the process of the present invention were described by sensory panellists as having a more green and biscuitlike character than spirit produced by conventional processes.

The process of the present invention results in a reduction in mashing times, saving typically 8 hours in the cycle time. There are also additional energy savings, since no hot water is required for mashing.

The process is environmentally friendly since it reduces reliance on cooling towers and cooling water disposal. An unexpected corollary of having husks and spent grains present during the initial distillation is that the distillation mixture is less likely to froth over in the pot stills.

Claims

CLAIMS:

1. A process for the production of whisky comprising the steps of: (i) forming a mixture comprising milled malt and water at a temperature in the range of from 14 to 26"C; (ii) adding yeast to the mixture from step (i) and allowing the resulting mixture to ferment; and (iii)distilling the fermented mixture from step (ii)

2. A process as claimed in claim 1, wherein the temperature at which the mixture of step (i) is formed is in the range of from 16 to 240C.

3. A process as claimed in claim 1 or claim 2, wherein the temperature at which the mixture of step (i) is formed is approximately 200C.

4. A process as claimed in any one of the preceding claims, wherein the yeast is added to the mixture from step (i) within 1 hour of forming the said mixture.

5. A process as claimed in any one of the preceding claims, wherein the yeast is added to the mixture from step (i) within 5 minutes of forming the said mixture.

6. A process as claimed in any one of the preceding claims, wherein the yeast is added to the mixture from step (i) by conveying the mixture from step (i) concurrently with the yeast into a fermentation vessel.

7. A process as claimed in any one of the preceding claims, wherein the resulting mixture from step (ii) is allowed to ferment adiabatically.

8. A process as claimed in any one of the preceding claims, wherein the resulting mixture from step (ii) is allowed to ferment for a period of time in the range of from 40 to 100 hours.

9. A process for the production of whisky comprising the steps of: (a) forming a mixture comprising milled malt and water at a temperature in the range of from 14 to 260C; (b) forming a mixture comprising milled malt and water at a temperature in the range of from 60 to 70 CC; (c) cooling the mixture from step (b) to a temperature in the range of from 14 to 260C; (d) forming a mixture comprising yeast, the mixture from step (a) and the mixture from step (c) and allowing the resulting mixture to ferment; and (e) distilling the fermented mixture from step (d).

10. A process as claimed in claim 9, wherein the temperature at which the mixture of step (a) is formed and/or the temperature of step (c) is in the range of from 16 to 24 cm.

11. A process as claimed in any one of claim 9 or claim 10, wherein the temperature at which the mixture of step (a) is formed and/or the temperature of step (c) is approximately 20"C.

12. A process as claimed in any one of claims 9 to 11, wherein the mixture of step (d) is obtained by combining the mixture from step (a) and the mixture from step (c), followed by adding the yeast.

13. A process as claimed in claim 12, wherein the mixture of step (d) is obtained by conveying the mixture from step (a) concurrently with the mixture from step (c) into a fermentation vessel, followed by adding the yeast.

14. A process as claimed in claim 12 or claim 13, wherein the yeast is added within 1 hour of combining the mixture from step (a) and the mixture from step (c).

15. A process as claimed in any one of claims 12 to 14, wherein the yeast is added within 5 minutes of combining the mixture from step (a) and the mixture from step (c).

16. A process as claimed in any one of claims 9 to 11, wherein the mixture of step (d) is obtained by first adding the yeast to the mixture from step (c) followed by adding the mixture from step (a) to the mixture from step (c) and yeast.

17. A process as claimed in claim 16, wherein the mixture from step (a) is added within 1 hour of adding the yeast.

18. A process as claimed in claim 16 or claim 17, wherein the mixture from step (a) is added within 5 minutes of adding the yeast.

19. A process as claimed in any one of claims 16 to 18, wherein the mixture from step (a) is added to the mixture from step (c) and yeast by conveying the mixture from step (a) concurrently with the mixture from step (c) and yeast into a fermentation vessel.

20. A process as claimed in any one of claims 9 to 11, wherein the mixture of step (d) is obtained by conveying the mixture from step (a), the mixture from step (c) and the yeast concurrently into a fermentation vessel.

21. A process as claimed in any one of claims 9 to 20, wherein the resulting mixture from step (d) is allowed to ferment adiabatically.

22. A process as claimed in any one of claims 9 to 21, wherein the resulting mixture from step (d) is allowed to ferment for a period of time in the range of from 40 to 100 hours.

23. A process as claimed in any one of the preceding claims, wherein the milled malt is obtained from Puffin, Derkado, Delibes or Maresi barley varieties or a mixture of two or more thereof.

24. Whisky whenever produced by a process as claimed in any one of the preceding claims.

25. A process for the production of whisky substantially as hereinbefore described with reference to any one of Examples 1, 3, 4, 5 to 7, 9 to 11 and 13.