Malting, Brewing and Distilling Introduction relevant to the country of origin and the descrip- The essential process involved in brewing is tion of the product. Consequently, added enzymes the conversion of cereal starch into alcohol to may contribute different proportions of the enzyme make a palatable, intoxicating beverage Fermen- complement The alcohol content of the liquor produced by tation is mediated by yeasts appropriate to the fermentation is limited by the tolerance of the cereal or cereals involved. Most yeasts used belong to the species Saccharomyces cerevisiae. yeasts. Probably the most tolerant yeasts are used which now includes the ' bottom yeast'previ in sake production. They can survive alcohol ously classified as S. carlsbergensis(Reed ar contents of about 20% although the Nagodawithana, 1991) sold in a diluted form Two processes are involved: the starch has first Distillation allows the concentration of alcohol enzymes, and second, the sugars have to be character of which depends on flavours imparted fermented to alcohol by enzymes present in yeast. added flavours usually being extracts from other In the first process the enzymes may be producc plant sources. exogenously, in other organisms present. Alter For alcohol production from plant material, natively they may be added as extracts sugars must be present, as in fleshy fruits, or other substrates from which fermentable sugars are employed is known as malting. This comprises can be produced. Starch is such a substrate,so a controlled germination during which enzymes capable of catalyzing hydrolysis, not only of the West, the most commonly used cereal is starch,but also other components of the grain, barley but substantial quantities are derived from are produced. The most significant are the pro- maize(beer in central America), rye(kvass beer teases and the B-glucanases, as the products in the former U.S.S. R), rice(sake in Japan and resulting from their activities affect the qualiti shaoshinchu in China), sorghum(beer in Africa). of the beverage Triticale may be used as an adjunct in beers Other organisms are employed as a source of zymes in the production of sake -a beer produced from rice. Enzymes are added in solu- Malting tion, particularly when it is required to hydrolyze During malting, large molecular weight com- he starch etc. present in endosperm grits or ponents of the endosperm cell fours, themselves incapable of enzyme produc- proteins and the starch granules, are hydrolyzed tion. Such adjuncts may provide any proportion by enzymes rendering them more soluble in of the total starch, depending on legislation water9 Malting, Brewing and Distilling Introduction The essential process involved in brewing is the conversion of cereal starch into alcohol to make a palatable, intoxicating beverage. Fermen￾tation is mediated by yeasts appropriate to the cereal or cereals involved. Most yeasts used belong to the species Saccharomyces cerevisiae, which now includes the ‘bottom yeast’ previ￾ously classified as S. carlsbergensis (Reed and Nagodawithana, 1991). Two processes are involved: the starch has first to be converted to soluble sugars by amylolytic enzymes, and second, the sugars have to be fermented to alcohol by enzymes present in yeast. In the first process the enzymes may be produced in the grains themselves (endogenously) or exogenously, in other organisms present. Alter￾natively they may be added as extracts. The process in which the grain’s own enzymes are employed is known as malting. This comprises a controlled germination during which enzymes capable of catalyzing hydrolysis, not only of starch, but also other components of the grain, are produced. The most significant are the pro￾teases and the P-glucanases, as the products resulting from their activities affect the qualities of the beverage. Other organisms are employed as a source of enzymes in the production of sake - a beer produced from rice. Enzymes are added in solu￾tion, particularly when it is required to hydrolyze the starch etc. present in endosperm grits or flours, themselves incapable of enzyme produc￾tion. Such adjuncts may provide any proportion of the total starch, depending on legislation water. relevant to the country of origin and the descrip￾tion of the product. Consequently, added enzymes may contribute different proportions of the enzyme complement. The alcohol content of the liquor produced by fermentation is limited by the tolerance of the yeasts. Probably the most tolerant yeasts are used in sake production. They can survive alcohol contents of about 20% although the product is sold in a diluted form. Distillation allows the concentration of alcohol into drinks described as spirits, the special character of which depends on flavours imparted by the processing or added to a distillate, the added flavours usually being extracts from other plant sources. For alcohol production from plant material, sugars must be present, as in fleshy fruits, or other substrates from which fermentable sugars can be produced. Starch is such a substrate, so all cereals can be used for beer production. In the West, the most commonly used cereal is barley but substantial quantities are derived from maize (beer in central America), rye (kvass beer in the former U.S.S.R), rice (sake in Japan and shaoshinchu in China), sorghum (beer in Africa). Triticale may be used as an adjunct in beers. Malting During malting, large molecular weight com￾ponents of the endosperm cell walls, the storage proteins and the starch granules, are hydrolyzed by enzymes, rendering them more soluble in 21 8