Technical Field

The present invention relates to a process for preparing an alcohol bearing solution.

Background of the Invention

There are two principal classes of alcoholic beverages, namely fermented beverages and distilled beverages. Fermented beverages include beer, wine, cider and sake; whereas, the distilled beverages include the spirits and liqueurs. The alcohol in all alcoholic beverages is derived from the fermentation of sugar, the source of which is typically a grain. Very generally, distilled beverages are prepared by fermenting a source of fermentable sugar in the presence of yeast to produce an alcohol rich solution and then distilling the alcohol from that solution.

The flavour of conventional spirits depends largely on the kind and amount of the fermentable sugar and yeast used, plus variations in the mashing, fermentation, distillation and aging processes. All of these things contribute to the type and amount of congeners in the finished product. Congeners may be defined as compounds (typically aldehydes and esters) retained in alcoholic beverages which significantly contribute to the flavour characteristics of the beverage.

The source of fermentable sugar in whisky is a grain. Whisky can be produced from any grain, but corn, rye and barley are the principal grains used. Different styles of American whisky use different grains and combinations of grains to achieve different flavours in the end product. However, basically all use barley malt as the source of enzymes which convert the starch in the grain to fermentable sugar. The American process typically uses a continuous or column still to distil off the alcohol produced in the fermentation process.

Scottish malt whisky is produced exclusively from barley malt. The malt therefore is the source of fermentable sugar, in addition to providing the enzymes, α-amylase and β-amalyse which convert the grain starch to fermentable sugar, which is principally maltose. The malt is prepared by exposing the barley to moisture which artificially germinates the grain in a process termed "steeping". "Malting" follows steeping in which the germination is continued and the starches are converted to sugars. The malt, which the barley has now become, is dried slowly in a kiln, care being taken to ensure that the kiln temperature does not rise above 70°C which would, destroy the malt enzymes. During drying, peat is commonly used as a fuel with the products of its combustion adhering to the malt giving rise to a characteristic flavour which is evident in the final product. The final stage in the preparation of malt is "gristing" in which the product of the malting is ground to the required specification to produce what is termed "gristed malt".

The sugars are extracted from the gristed malt in a process called "mashing" in which the gristed malt is stirred with hot water at a temperature of 60°C-68°C. If the temperature is too low, the sugars are difficult to extract and if the temperature is too high, the enzymes may be destroyed. During mashing, the conversion of starch to fermentable sugar which began in the malting process, is continued. The process is carried out in an insulated vessel called a "mash tun" in which the mash is mechanically mixed and kept at a temperature of about 65°C for a period of approximately 2 hours. The resultant clear liquid "wort" is filtered from the residual grain in a process called "lautering". The wort is cooled to about 27°C and pumped into a fermenting vessel called a "washback".

Yeast is pitched into the wort in the wash back and the wort is fermented producing the "wash". When fermentation is completed, the wash, is typically filtered leaving a mixture of

liquids, each of which boils at a different temperature. The main constituents are water and ethanol, but smaller amount of propyl, butyl and amyl alcohols and other components are also present. In the Scottish process, the fermented wash is distilled in a double distillation process. Both stills are pot stills, as distinct from the previously mentioned continuous still. The wash, containing about 6% alcohol by weight, is transferred to a copper pot still termed the "wash still" and the wash is heated until it boils. The vapours are condensed in a condenser and the resulting distillate termed the "low wines" is collected in a receiver. The low wines, now containing about 15% alcohol by weight are transferred into a second copper pot still, termed the "spirit still" together with some of the distillate from an earlier spirit still distillation. This mixture is distilled and the first run of distillate off the still is termed the "foreshot" which is typically a high alcohol content acidic liquid which is pumped to the "feints and foreshots receiver" for subsequent re-distillation. Following the foreshots, a potable fraction is collected which is transferred to the whisky receiver. The whisky fraction is tested during distillation and when the composition falls outside pre-determined limits, the distillate ceases to be transferred to the whisky receiver and the remaining distillate, termed the "feints", is pumped to the feints and foreshots receiver.

The newly distilled whisky typically possesses a harsh flavour and is therefore matured in oak casks which are stored in cool warehouses for three to ten years or more. The maturation is thus a long, slow and hence expensive process. During maturation, the whisky acquires flavour from the oak casks and some of the alcohol is believed to be converted to esters which add to the flavour of the end product.

The Scottish also make grain whiskys which are similar to American whiskys in that the fermentable sugar is derived

from grains other than the barley malt. The distillation process however, is basically the double distillation process described above.

Gin is prepared by either direct distillation or re-distillation. In direct distillation, a fermented grain mash is pumped into a still and heat is applied. At the top of the still, a "gin head" is packed with juniper berries and herbs so that as the alcohol vapour passes through the gin head into the still head, it extracts the typical juniper flavour. The resulting condensed liquid is gin. The re-distillation process is basically the same, except that the fermented mash is initially distilled to a flavourless neutral spirit and then it is re-distilled, passing the vapours once again through a gin head to extract the juniper flavour.

In the preparation of rum, the source of fermentable sugar is not a grain, but rather molasses. The molasses, water and yeast are fermented and the resulting alcohol rich solution is distilled to yield rum.

Vodka is a distillate of the fermented mash of a grain which is typically barley, corn or rye, but it may also be made from potatoes. Unlike whisky, which is distilled at low alcoholic strength to retain congeners, vodka is distilled at high alcoholic strength to retain a minimum of congeners and is then processed still further to extract all remaining congeners. Vodka is somewhat like gin in that both are made from grain neutral spirits and neither has to be aged. In gin, the flavour is added by the addition of juniper and aromatics as previously described; whereas, in vodka all flavour and character is removed to leave an odourless, tasteless, colourless and smooth spirit.

In contrast to the previously discussed "dedicated" processes, the present invention provides a process for preparing an alcohol bearing solution which can be diluted or

concentrated and/or blended with a variety of flavouring and/or colouring essences and additives to produce a liquid suitable for use in a pharmaceutical or as a beverage.

Summary of the Invention

Accordingly, the present invention provides a process for preparing an alcohol bearing solution comprising the steps of:

(a) dissolving a malted grain and/or malt concentrate and a source of fermentable sugar in water to yield a wort,

(b) fermenting the wort in the presence of a beer style yeast and a wine style yeast to yield a wash, and

(c) distilling the wash to yield an alcohol bearing distillate.

Unlike conventional processes which typically include preparation of malt, the present invention commences with a malted grain or malt concentrate. The conventional steps of steeping, malting, gristing, mashing and lautering are therefore eliminated and replaced by single step which simply involves the mixing of the malted grain and/or malt concentrate and the source of fermentable sugar in water to yield the wort.

The malted grain of the present invention is preferably a malted barley. The process preferably uses a malt concentrate in which case the amount of raw material required is decreased. The malt concentrate is preferably a pale dried malt extract and is more preferably WANDER 1212 which is believed to contain approximately 12% unfermentables and is available from WANDER (AUSTRALIA) Pty. Ltd., Melbourne. The preferred source of fermentable sugar is a refined cane or beet sugar and is most preferably refined white table sugar.

The dissolution of the source of fermentable sugar and the malted grain and/or malt concentrate is typically performed in a vessel termed a "brew kettle". Preferably, the water is added to the brew kettle and brought to a temperature of 80°C-100°C to partially sterilize the kettle. The malt or malt extract and the source of fermentable sugar are added with a resultant decrease in temperature and the mixture gently agitated to assist with dissolution. Following dissolution, the resultant wort is cooled and transferred to a "wash back" ready for fermentation. For efficiency of cooling, the wort is desirably pumped from the brew kettle to the wash back through a heat exchanger. Additional water may be added to the brew kettle prior to transfer, to the wash back, or even to both to assist with cooling. It should be noted that the object of this part of the process is simply to dissolve the solid raw materials in the water in preparation for fermentation and therefore the temperatures, the amounts of water and the method or order in which the raw materials are dissolved are largely irrelevant. Temperatures in the ordef of 100°C are desirable principally from a steralization point of view rather than as a necessity for dissolution.

WANDER 1212, refined white table sugar and water are most preferably used in the weight ratio of 1:3.75:25. The amount of water can obviously be varied but too little water will make dissolution difficult and too much water will produce an unnecessarily voluminous wash. Advantageously, 40% of the water is added initially with the balance added after dissolution to assist in cooling. The ratio of WANDER 1212 to refined white table sugar can also be varied but as the amount of WANDER 1212 is reduced, so too will the flavour level of the end product. Conversely, as the proportion of WANDER 1212 is increased, the wash becomes sweeter and more flavoursome; whereas, a reasonably dry wash is preferable. It is therefore preferred that the ratio of WANDER 1212 to refined white table sugar is between 1:7 and 2:3 on the basis of weight.

Raw materials other than the most preferred WANDER 1212 and refined white table sugar may be used, in which case, the proportions of raw materials would be varied accordingly. For example, if a malted grain were used in place of the malt concentrate, a greater amount of malted grain would be required and the weight ratio of malted grain to refined table sugar would be in the order of 1:1.

The wort is preferably cooled to between 20°C-35°C and the beer style yeast and wine style yeast are preferably pitched reasonably quickly after cooling to avoid contamination of the wort by a wild yeast or other infection of the wort. In addition to the yeast, yeast nutrients are also preferably added. The preferred yeast nutrients are vitamin B, vitamin C and diammonium phosphate. For optimum results, the fermenting wash is preferably maintained at a reasonbly constant temperature by warming and cooling as necessary. The preferred temperature is 25-30-C. The pH of the fermenting wash is preferably in the range 3.5-4.5 and is most preferably 4.0. As the acidity or alkalinity increases, the fermentation will slow down and the flavour of the resultant wash will be affected. This is to be contrasted with most known fermentation processes in which the pH is generally maintained in the range 5.0-5.8.

The attenuation period is typically seven to ten days, which is longer than in conventional processes, producing a wash with a typical alcohol content of approximately 8-10 a/v. The s.g. is typically in the range of 0.998-1.005 at the completion of fermentation for a wash which had an initial s.g. of approximately 1.070.

Conventional distilling yeasts are not well suited for use in the invention as they do not yield a strong (high alcohol) wash which is typical of the present invention. The preferred yeast is therefore a yeast or a combination of yeasts which combine the characteristics of a beer style yeast

with those of ^ dry white wine style yeast, whereby the beer type characteristics provide strong flavoursome fermentation at lower alcohol concentration and the dry white wine characteristics enable the fermentation to continue beyond the point where beer style yeasts begin to "tire" which is typically at about 7-8 a/v. In theory, the wash could be prepared in a two stage fermentation process in which the wort was initially fermentated in the presence of a beer style yeast and subsequently in the presence of a wine style yeast for continued fermentation. For convenience and in practice however, the yeast is preferably pitched in one step and consists of a colony of two component yeasts which share the same medium and largely function as each would if it were independent of the other.

A variety of yeasts including the beer yeasts, Coopers Beer Yeast available from Cooper & Son, Adelaide, Australia; Edme Brand Distillers Yeast available from Distillers Corporation Limited, London; Wander Yeast available from Wander (Australia) Pty Ltd, Melbourne, Australia; and the wine yeasts, Proferm Yeast available from Fermentation Laboratories, Burton on Trent, England; Proferm Sherry Yeast available from Fermentation Laboratories, Burton on Trent, England; All Purpose Wine Yeast available from the Vigneron's Co-Operative of South Australia have been satisfactorily used in various combinations in the process of the present invention. The most preferred yeast combination is a 50:50 starting dry culture of Edme Brand Distillers Yeast and Proferm Yeast, both of which are of the genus Saccharomyces.

The types and relative proportions of the yeasts used have a bearing on the base spirit ultimately produced and hence the process can be tailored by yeast selection. The aforementioned combination is preferred as it has proven to produce a desired base spirit but is should be understood that any combination of a good quality beer style yeast and a good quality wine style yeast can be used in the process of the invention.

Typically, a series of fermentations will be conducted in a batch wise manner in the one wash back. In such a situation, a small quantity of wash is preferably retained in the wash back for fermentation of a fresh wort. The retained wash would generally be in the order of 1% of a fresh wort and would typically contain a relatively high concentration of yeast. To ensure continuation of the yeast colony, this procedure would generally only be repeated four or five times, after which a fresh yeast culture would be introduced with the addition of yeast nutrients as required.

In contrast to most conventional processes which filter washes to varying degrees, in the present invention, the yeast is preferably not filtered from the wash prior to distillation. Such distillation of washes containing suspended yeast has been observed to impart a desirable bite to the resultant alcohol bearing distillate which for convenience is termed the "base spirit".

Distillation may be performed in a continuous still but is preferably performed batch wise in a pot still. More preferably the wash is double distilled, initially in a wash still and subsequently in a spirit still for refinement of the base spirit.

Unlike the Scottish process however, the pot stills which are preferred for use in the present invention differ from conventional pot stills in a number of ways. For hygiene reasons, the bodies of the stills are preferably made from stainless steel which is easier to clean than conventional copper stills. Stainless steel also has the advantage that it is inherently stronger than copper and therefore less bracing is required within the body of a still with a resultant lessening of pockets within which bacteria may accumulate. The use of stainless steel bodies also eliminates the possibility of copper oxide being carried into the end product which is seen as being undesirable as copper oxide may be

associated with arthritis. The condensors are preferably made of copper as in known configurations as research has indicated that stainless steel condensors are less efficient and tend to give a burnt taste to the base spirit.

Brief Description of the Drawings

Figure 1 is a profile of a typical pot still used in conventional processes.

Figure 2 is an illustration of a pot still preferably used in the present invention.

Classical pot stills, as illustrated in Figure 1, have tall chimneys (10) which taper away from the body of the still (11). The chimney (10) often contains a bell (12) which is an area of increased diameter at its lower end. The object of this conventional arrangement is to promote reflux; whereas, by contrast, the preferred pot stills of the present invention, as illustrated in Figure 2, seek to limit reflux. The stills of the present invention therefore preferably do not have the classical bell shaped chimney between the top of the still body an the condenser, but rather have a proportionally smaller diameter, non-tapering conduit (13). The result of this modification to a conventional still configuration is that the distillate is more flavoursome and has greater body. Although the stills of the present invention seek to limit reflux, they still seek to avoid fusel oils being carried over into the distillate.

As previously mentioned, the present invention preferably employs a double distillation process in which case the wash is transferred to a wash still for primary distillation and in contrast to known distillation processes, the wash is not filtered to remove yeast and other suspended matter prior to distillation. Primary distillation is preferably carried out in the conventional manner yielding low

wines. Typically, a quantity of feints and foreshots from a previous secondary distillation are added to the wash prior to primary distillation with low wines beginning to condense at a still temperature in the order of 88°C. Typical head up and distillation times are 2-2.5 hrs and 7.5-8.5 hrs respectively with the distillation generally being terminated when the alcohol concentration in the wash distillate falls to approximately 5 a/v.

The low wines, which typically have an alcohol concentration in the order of 50 a/v, are transferred to the spirit still for secondary distillation. Again, the secondary distillation preferably follows the conventional process with a foreshot fraction removed to a feints and foreshots receiver prior to changing to the spirit receiver for retention of the potable fraction. Distillation of the potable fraction continues to a pre-determined point from which time the feints are transferred to the feints and foreshots receiver. As is the case in conventional secondary distillation, the feints and foreshots from one distillation are preferably returned to the spirit still for re-distillation with a new batch of low wines.

In a typical distillation, 100 1 of wash will produce approximately 25-30 1 of low wines following primary distillation, which in turn would typically yield approximately 8-10 1 of potable spirit following secondary distillation.The foreshot of the secondary distillation is not potable because of the esters, acids, aldehydes and ketones that it contains together with its very high alcohol concentration which is typically in the order of 90 a/v. Approximately one 1 of foreshots would be removed from secondary distillation of the 25-30 1 of low wines previously mentioned. Following removal of the foreshots, distillation to the potable fraction would typically continue until the distillate fell below approximately 50-60 a/v at which time the distillate would be directed back to the feints and

foreshots receiver for collection of the feints. The point at which the distillation is cut from the potable fraction to the feints is understood to be considerably lower than in conventional processes. The alcohol concentration of the resulting potable base spirit is typically approximately 75-80 a/v.

Although the base spirit of the present invention may be used in its uncut form, it is preferably concentrated, dilluted and/or blended with a variety of flavouring and/or colouring essences and additives depending upon the characteristics desired of the end product. Potential uses of the end product are as a constituent of pharmaceutical preparations or in alcoholic beverages.

Base spirit prepared according to the present invention has been cut with water and blended to produce end products which mimic a variety of well known spirits and liqueurs with the substantial advantage that traditional maturation periods are not required.

A variety of colourings and flavourings including Bourbon Essence DC15114, Gin Essence AD86693, Rum Essence DC14390, Whisky Essence NN05806, Oak Essence NN05806, Oak Essence 12695, Caramel S 008020 CL, Mango Essence DC12325,

Orange Essence DC11316, Brandy Essence 12520, Cherry Surprise Essence CS11994.02, Orange Colour 5Y0L008 and Wild Peach Essence DC16952 have been blended with base spirit. All the aforementioned colourings and flavourings are available from Quest International, Kensington, Melbourne, Australia.

By way of example only, the following spirit mimicking styles have been prepared by blending uncut base spirit having an alcohol concentration of 75 a/v with an equal volume of water and then making the noted additions.

Gin style: 30ml of Gin Essence AD86693 is added for each 5 1 of cut base spirit.

Light-bodied whisky style: to every 51 of cut base spirit is added 5ml of Caramel S 008020 CL + 10ml of Oak Essence 12695 + 5ml of Whisky Essence NN05806.

Heavy-bodied whisky style: to every 5 1 of cut base spirit is added 10ml of Caramel S 008020 CL + 10ml of Oak Essence 12695 + 10 ml of Whisky Essence NN05806 + 150ml of port + 150ml of sherry.

Rum style: to every 5 1 of cut base spirit is added 15ml of Caramel S 008020 CL ÷ 10ml of Oak Essence 12695 + 15ml of Rum Essence DC14390.

Bourbon style: to every 51 of cut base spirit is added 5ml of Caramel S 008020 CL + 10ml of Oak Essence NN05806 + 30ml of Bourbon Essence DC15114.

The above mentioned additives are by no means exhaustive and a large variety of spirit and liqueur style beverages can be prepared. Particularly with regard to liqueur style beverages, a large variety of fruit essences may be incorporated. Additives can be selected from commercially available flavourings and essences or may be specially prepared to suit a particular end product. For example, a large number of fruit flavourings can be extracted from the fruits themselves, caramel flavouring can be prepared by the caramelization of sugar and oak essence can be prepared by soaking oak turnings in the base spirit.

The preferred embodiments of the present invention provides a number of significant advantages over conventional processes and these may be summarised as follows.

As the steps of steeping, malting, gristing, mashing and lautering are not required, the physical scale of an operating distillery is substantially reduced. The aforementioned steps are complex, delecate, capital intensive and require the input

of a range of highly skilled personnel. Due to the decrease in scale, process quality is more readily controlled as the risk of product contamination is substantially decreased.

The process is not directed to the preparation of any particular end product. Such a non-dedicated process provides a maximum of flexibilty and as will be readily apparent from the foregoing description of the process, alterations to process parameters can be made all the way from raw material input to blending of base spirit. Perhaps the single greatest advantage of the present invention is that a common base spirit can be prepared for subsequent use in the preparation of a vast number of end products without the restriction of aging times required of a number of conventional processes. This feature of the present invention is obviously significant when faced with fluctuating market demand.

Best Mode of Carrying out the Invention

One preferred embodiment of the invention will now be described by way of example only which should not be construed as limiting the scope of the invention in any way.

A brew kettle was sterilised by boiling 40 1 of water. The water was then allowed to cool to 85°C at which time 15 kg of refined wh$fte table sugar and 4 kg of WANDER 1212 were added with the temperature falling to 80°C. The mixture was gently agitated to assist dissolution of the raw materials. The resultant wort was maintained at 80°C for 20 minutes and then pumped through a heat exchanger to a wash back with the temperature falling to 35°C. An additional 60 1 of water was added to the wash back bringing the wort temperature to 30°C. Prior to addition of the wort, the wash back contained 1 1 of wash from a previous fermentation which contained a high concentration of a 50:50 mixture of Edme Brand Distillers

Yeast and Proferm Yeast. The temperature was dropped to and maintained at 5°C by heating and cooling coils within the

wash back and the onset of fermentation was observed through bubbling of the wash after 2 hrs. Throughout attenuation, the wash was maintained at about 25°C with a pH of approximately 4.0. The wort initially had an s.g. of 1.070 at 20°C and at the completion of fermentation after ten days, the wash had an s.g. of 1.002 at 20°C giving a potential average alcohol concentration of the wash of the order of 9.52 a/v.

The wash was then transferred without filtration to a wash still having a stainless steel body, a copper condensor and profile as illustrated in figure 2. One litre of the wash containing a high concentration of yeast was retained in the wash back for a subsequent fermentation. Eight litres of feints and foreshots from a previous spirit still distillation was added to the wash still which was heated by two stainless steel single phase 35 amp electric elements. After 2 hrs and 15 mins and at a wash temperature of 88°C, the low wines began to distil over to the spirit still which was substantially identical to the wash still but of a lesser scale. Primary distillation was discontinued after 8 hrs when the alcohol concentration in the distillate fell to 5 a/v. The primary distillation yielded 28 1 of low wines having an alcohol concentration of 50 a/v.

Secondary distillation in the spirit still commenced at a low wines temeprature of 79°C and the initial one litre of foreshots was transferred to the feints and foreshots receiver. The distillate was then collected in a base spirit receiver until the alcohol concentration of the distillate fell to 60 a/v which produced 8 1 of base spirit having an alcohol concentration of 80 a/v. The distillate was then re-directed to the feints and foreshots receiver and distillation continued until 8 1 of feints were collected at which time the low wines temperature was 99°C.