THE MICROBE OF BEER 67 



soaked in water until all its soluble parts are dis- 

 solved. The insoluble parts which remain in the 

 liquor are now filtered out, and the clear liquid 

 is called wort. This wort is sweet; it contains all 

 the starch of the barley changed into sugar. It 

 also contains the bitter principle extracted from 

 the hops. 



Now comes the critical point to convert this 

 wort into beer. For this purpose the brewer has 

 on hand a beer yeast. This yeast is taken from 

 the previous brewing. Every brewing produces 

 two kinds of yeast. The scum is one kind, con- 

 taining a certain species of microbes. The set- 

 tlings are another kind, containing a different 

 species of microbes. The beer brewed from the 

 scum is known as superior; that brewed from the 

 settlings is known as inferior. The brewer having 

 on hand the desired kind, applies a sufficient 

 amount to his wort, and thoroughly stirs it. 



Every drop of this yeast contains millions upon 

 millions of the tiny microbes. The sugar of the 

 wort is the natural food of these beings. On it 

 they begin to subsist, grow, thrive, and multiply 

 with great rapidity, until they fill every drop of 

 the wort completely. 



The wort ferments and foams. But this fer- 

 menting process is wholly caused by the microbes. 

 In subsisting on the sugar, by their life processes, 

 eating, digesting, excreting and multiplying, 

 they convert the sugar into alcohol and carbon 

 dioxide. The alcohol, it need not be said, is the 



