Preparation of wort extracts

A method for producing a wort containing a reduced level of fermentable sugars is described. The method consists of providing a warm aqueous suspension of ground malt, and adding the warm suspension to a boiling aqueous suspension of cereal adjuncts while avoiding temperatures between about 52.degree. and 72.degree. C. The resulting wort is useful for producing a beer with a lower-than-normal alcohol content, or a malt beverage lacking sweetness usually associated with malt beverages.

FIELD OF THE INVENTION 
The present invention relates generally to a method for preparing a wort 
extract. More particularly, the invention relates to a method for 
preparing an extract of malt containing a reduced level of simple, 
fermentable sugars. The wort extracts may be used in a traditional brewing 
process, for producing a beer of reduced alcohol content, or for producing 
a non-alcoholic malt beverage lacking in sweetness usually associated with 
such malt beverages. 
DESCRIPTION OF THE PRIOR ART 
In the production of beer, yeast is used to ferment into ethyl alcohol a 
substrate made of a mixture of fermentable carbohydrates so called "wort 
carbohydrates." The wort carbohydrates involved which can be fermented by 
Brewers' yeast are normally maltose, glucose, maltotriose and traces of 
sucrose and fructose. They are obtained by allowing malt enzymes (alpha 
and beta amylase) to transform starch molecules from malt and other 
adjuncts into the fermentable sugars outlined above. This is done during 
the so-called mashing operation. 
Conventional mashing involves mixing together of malt and cereal adjuncts 
in hot water, followed by a series of heating and resting cycles. 
Substances which are solubilized in the hot water are collectively called 
the extract. Following mashing, the soluble materials are extracted during 
lautering, leaving behind the spent grain. A clear liquid (wort) obtained 
by the extraction may then be transferred to a brew kettle and boiled for 
a period of time (kettle boiled) which inactivates the malt enzymes. Wort 
compositions vary depending on the raw materials and mash cycle employed. 
A typical wort used in brewing may comprise the mixed extract of a barley 
malt mash and a cereal adjuncts mash typically of corn grits or rice. Such 
mixed extract may be obtained by treating a kiln dried barley malt with 
warm water, at about 50.degree. C., in one vessel, the so-called "mash 
tub", and boiling the cereal adjuncts, (e.g. corn grits or rice) in 
another vessel, the so-called "cooker," and then adding the boiling 
contents of the cooker to the warm malt suspension in the mash tub. This 
serves to raise the temperature of the mash tub contents to about 
57.degree.-67.degree. C. During the rise from 50.degree. C. to about 
67.degree. C., and starting at around 63.degree. C., the enzymes in the 
malt and in particular beta-amylase which is most active between 
60.degree. and 70.degree. C., partially degrade the starches in both the 
malt itself and in the corn grits or rice to form simple fermentable 
sugars, primarily glucose, fructose and maltose. These simple sugars are 
fairly sweet tasting, and also are fermentable by Brewers' yeast to 
alcohol and carbon dioxide. 
Enzymatic processes dominate the entire mashing process and are the direct 
continuation and completion of processes initiated during the steeping and 
germination of the malt and suspended abruptly by the drying action of 
kilning. The time span utilized in adding the cooker contents to the mash 
tub and the temperature of the combined mash (and rest times) determine 
the proportion of fermentable sugars in the wort, and the wort's 
sweetness. This proportion, in turn, determines the degree of 
fermentability of the wort. Typically, an addition time of five to fifteen 
minutes coupled with a subsequent rise in temperature caused by injection 
of live steam or by contact with a heated surface, will result in a major 
amount of the available starch being converted to fermentable sugars. 
Those breweries which use, instead of corn grits or rice, a prehydrolized 
corn syrup, which does not need to be either boiled or acted upon by malt 
enzymes, may either add just boiling water to the mash tub to secure the 
aforesaid rise in temperature, or provide adequate heating surface to heat 
the mash tub quickly. In either case, the level of fermentable sugars 
typically may vary between 50 and 75% by weight. This has suited the 
purposes of breweries worldwide. 
Recently, there has developed consumer interest in beers of reduced 
alcoholic content and/or non-alcoholic malt beverages lacking in 
sweetness. Typically, reduced alcohol content beer is formed by brewing 
beer in a conventional manner and diluting the beer with water, or by 
mixing a typical, fermented malt beverage with about equal volumes of 
unfermented wort, or by attempting to reduce the time span between 
50.degree. C. and 75.degree. C. by rapid addition of boiling water, or by 
physically removing a part of the alcohol from the fermented product. Such 
processes are not entirely satisfactory, since the resulting products are 
beers of reduced flavor intensity. 
It is thus a primary object of the present invention to provide a new and 
improved process for producing an extract of malt which overcomes the 
aforesaid and other disadvantages of the prior art. Another object of the 
present invention is to provide a novel and improved process for producing 
a wort containing a reduced level of simple, fermentable sugars. Still 
other objects of the present invention are to provide a method for 
producing a beer of reduced alcohol content, or a malt beverage lacking in 
sweetness. A specific object of the invention is to provide a novel and 
improved method for producing a wort having a relatively low level of 
fermentable sugars, using existing equipment and materials. Still other 
objects of the invention will in part be obvious and will in part be 
apparent hereinafter. 
These and other objects of the present invention are achieved by processing 
a warm malt mash under conditions which avoid exposing the malt mash to 
temperatures between about 52.degree. C. and about 75.degree. C. In a 
preferred embodiment of the invention, the malt mash is added directly to 
the contents of the cereal cooker under conditions such that the 
temperature in the contents of the cooker does not fall below about 
75.degree. C. anytime during the addition, and specifically avoids the 
temperature range between about 52.degree. C. and about 75.degree. C. A 
wort extract is obtained having a reduced level of simple, fermentable 
sugars, which may then be further processed into beer lacking in alcohol 
content, or a malt beverage of reduced sweetness. 
The invention accordingly comprises the processes involving the several 
steps and relation of one or more such steps with respect to each other, 
and the materials and products possessing the features, properties and 
relations of elements, all of which are exemplified in the detailed 
description, and the scope of the application, which will be indicated in 
the claims. 
Generally, the process of the present invention comprises batch preparation 
of ground malt mash and a boiled cereal adjuncts. The ground mash is 
prepared by mixing a measured quantity of dried malt with warm water, e.g. 
in a mash tub. Typically, the water is maintained at a temperature in the 
range of 40.degree. C. to 50.degree. C., and not much higher than 
50.degree. C. After addition of all the malt the mash is then heated for a 
period of an hour or less. 
Concurrent with the formation of the malt mash in the mash tub, a measured 
quantity of cereal adjuncts such as corn grits or rice is mixed in water 
and heated to boiling in a cereal cooker. A small amount of malt, or other 
source of alpha-amylase, is added to the cooker. 
The contents of the mash tub are then added to the boiling cereal in the 
cooker. The malt mash first added to the boiling cereal substantially 
instantly is raised to a temperature of about 100.degree. C., with the 
successive quantities of the malt mash being heated to successively lower 
temperatures. The relative quantities of liquids in the cooker and mash 
tub are chosen so that the final temperature, i.e., upon completion of the 
addition of the entire malt mash to the ceral adjuncts, is at least about 
75.degree. C. At this temperature the sugar-producing beta-amylase is in 
large part inactive, while the alpha-amylase present is sufficiently 
active to break down the starches to soluble dextrins and thus provide the 
desired extract. This will be true as long as the temperature during the 
addition is maintained above 75.degree. C. 
If desired, small quantities of a heat-stable alpha-amylase may be added to 
the malt mash/cereal mixture to enhance the alpha-amylase action. 
The mash may then be filtered in a Lauter tub, mash filter or other means, 
and resulting wort boiled with hops, filtered, cooled and fermented with 
yeast in the usual manner to produce a beer, ale, malt liquor or stout. 
The resulting beer is characterized by a lower-than-normal alcohol 
content. Alternatively, the wort may be cooled, treated with any desired 
supplements such as lactic acid, and the resulting liquid mixture 
filtered, carbonated if desired, and packaged as a non-alcoholic malt 
beverage which is characterized as lacking sweetness. 
The present invention will be further described in the following working 
examples.

WORKING EXAMPLES 
The following examples, illustrative of the present invention, employ a 
conventional, two vessel brew house with a mash tub and a cereal cooker or 
boiler vessel. The mash tub and cereal cooker are tied to one another via 
a valved conduit, and a pump. The basic procedure was to suspend dried, 
ground barley malt in water, heat the resulting suspension to a desired 
temperature, and hold the resulting mash suspension at the desired 
temperature for a period of time. Concurrently, the cereal adjucts, if 
desired containing also a small amount of malt, are added to water and 
cooked (boiled) a period of time. The mash is then mixed into the boiling 
cereal, with stirring. In Example I, the malt is mashed in the mash tub 
and the cereal adjuncts (corn and malt) boiled in the cereal cooker. In 
Example II, the malt is mashed in the cereal cooked and the cereal 
adjuncts (rice and malt) boiled in the mash tub. 
EXAMPLE I 
11,000 pounds of corn grits and 1,100 pounds of barley malt were added to 
160 barrels of water, and the resulting mixture heated to boiling, with 
stirring, for thirty minutes in a cereal cooker. 
Concurrently, 17,000 pounds of malt were added to 170 barrels of water, and 
heated to 52.degree. C., with stirring, in a mash tub. The resulting malt 
mash was held at 52.degree. C. for fifteen minutes, and the contents of 
the mash tub were then rapidly pumped over into the cereal boiler, and 
stirred. The temperature of the resulting mixture at the completion of the 
addition of the malt mash was about 75.degree. C. 
The resulting wort was analyzed and was found to contain approximately 
twenty-five percent fermentable sugars, by weight. 
EXAMPLE II 
17,000 pounds of malt were added to 170 barrels of water in a cereal 
cooker, heated to 50.degree. C., and held at 50.degree. C. for fifteen 
minutes in the cereal cooker. 
11,000 pounds of rice and 110 pounds of barley malt were added to 160 
barrels of water in a mash tub, and heated to boiling, with stirring, for 
thirty minutes. 
The contents of the cereal cooker were then pumped over into the mash tub, 
and stirred. The temperature of the mixture at the completion of the 
addition of the malt mash to cereal adjucts was about 75.degree. C. One 
pound of high temperature alpha-amylase (Fungamyl brand, available from 
Novo Laboratories, Inc.), was added to the resulting mash blend, and the 
mixture stirred for fifteen minutes at 75.degree. C. The resulting mixture 
was then analyzed and was found to contain approximately twenty-five 
percent simple sugars, by weight. 
EXAMPLE III 
The wort prepared in Example I was filtered and the filtrate was boiled 
with one hundred pounds of hops, strained and cooled to about 10.degree. 
C. The resulting mixture was then transferred to a fermentation tank to 
which was added five hundred pounds of brewers yeast. The resulting 
mixture was allowed to ferment for seven days. After letting the yeast 
settle out, and filtering, the resulting filtrate beer was bottled. The 
alcoholic content was measured and determined to be two percent by weight. 
EXAMPLE IV 
A feature and advantage of the present invention is that the novel and 
desirable wort containing low levels of simple (fermentable) sugars may be 
prepared using existing manufacturing equipment, i.e., without involving 
any capital investment. If the available vessels for mashing and boiling 
are appropriately sized, the equipment can be used in a conventional 
manner, i.e. forming the mash in the mash tub, and boiling the cereal 
adjuncts in the cereal boiler. The principal difference in accordance with 
the present invention then involves reversing the addition of the mash to 
the boiling cereal. If, on the other hand, the available vessels for 
mashing and cooking are not appropriately sized so as practically and 
conveniently to practice the reverse addition according to the present 
invention, the mash tub may be used to boil the cereal adjuncts, and the 
cereal cooker used to form the malt mash. 
Certain changes may be made in the above processes without departing from 
the scope of the invention herein involved. For example, the wort may be 
processed as above described using only boiling water, i.e. without cereal 
adjuncts. Still other changes will be obvious to one skilled in the art. 
It is therefore intended that all matter contained in the above 
description shall be interpreted as illustrative and not in a limiting 
sense.