CHAPTER II 

 BEER 



Beer is an alcoholic beverage made from certain cereal grains by 

 transformation of the starch to sugar, dilution with water, and fermen- 

 tation with yeast. There is usually an addition of hops and sometimes 

 of materials containing sugar. The liquid before fermentation is 



called wort. 



TYPICAL COMPOSITION OF VARIOUS BEERS 



RAW MATERIALS AND MICROORGANISMS OF BREWING 



GRAINS EMPLOYED. Barley, rice and maize are the grains most commonly used, 

 wheat, rye and oats but rarely. Cane and beet sugars and syrups sometimes form 

 part of the fermentable material. 



YEASTS or BEER .--The yeast used is usually one of the many forms 

 of S. cerevisice. In some spontaneously fermented beer, other yeasts, 

 TorulcB and bacteria take part, but in ordinary beers most of these are 

 considered as disease-producing organisms and injurious. 



KINDS OF BEER. The principal varieties of beer are: lager beers, fermented with 

 bottom yeasts; ales, fermented with top yeasts (and Torula); porters, similar to ale 

 but dark in color owing to the use of caramelized malt; weisbiers, in which lactic 

 bacteria are abundant; and certain local types in which bacteria produce con- 

 siderable quantities of lactic and acetic acids. Many attempts have been made to 

 produce a beverage similar to beer but lacking the alcohol. The ''temperance 

 beers" are of this character. Some of them are made by restricting the fermen- 

 tation or by omitting it. These are little more than wort or decoctions of malt 

 and lack the products of fermentation to which much of the flavor of beer is due. 

 In others the beer is made in the usual way and then by various devices freed 

 from alcohol. The latter are more expensive to produce but are considered of 

 superior quality. 



622 



