A distinct feature of North American brewing practice is the use of adjuncts in the manufacture of beer. Adjuncts are non-malt materials which supply additional carbohydrates beyond the principal material, malted barley.

Although adjuncts are used mainly because they provide extract at a lower cost than that available from malt, there are other definite advantages. The use of adjuncts results in beers of lighter colour and greater brilliancy, while being less satiating, with a snappier taste, and with better physical stability and enhanced chillproof qualities.

The adjuncts used most commonly today are corn and rice, although barley, wheat and sorghum are sometimes used. All adjuncts have been preprocessed to some degree and are manufactured products derived from the cereal grain, as it is the starch fraction which is of interest to the brewer.

A great deal of judgment must be exercised in the selection of both types and amounts of malts and adjuncts to be used in a particular brew. Many brewers use 40% to 50% adjunct, while we prefer to use no more than 30%. We feel that a "grainy" flavour can be detected if the portion of adjunct is too high.

In our brewery, corn meal was the primary adjunct, with wheat also being used in one premium product. Corn syrup was under consideration, as the cereal cooker would no longer be necessary, but the high cost of syrup made its use prohibitive. In 1983, the advent of brewing American style beers required the useage of corn meal and syrup in tandem. Syrup provides more consistency in quality over periods of time, and with that major benefit considered, the cereal cooker was taken out of use in 1995.

The back of the Brewhouse. Glucose tank on left. Corn storage was on the top floor.

CEREAL COOKER

The starch of the adjuncts (except syrups) is in its native form, and is not easily attacked by the enzymes present in malt. Therefore, the adjunct, in our case corn meal, must be processed in the cereal cooker. The cereal cooker is a small, steam-jacketed stainless steel vessel located above the lauter tun and is fitted with a motor driven agitator.

Cooking the corn affects the solubilisation and gelatinisation of the starch granules. As the starch granules gelatinise, they swell and become extremely viscous. Therefore, a portion of the malt is added to the cooker. We add approximately 10% of the total corn weight in crushed malt. The alpha-amylase enzyme of the malt attacks the gelatinised starch, leaving it fluid prior to transfer to the mash mixer.

After a suitable period of time, the cooker mash is transferred to the mash mixer. This is accomplished by using a low velocity, high volume pump. The pump is designed to minimise damage to the malt husks which is essential in the lauter tun.

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