

YEASTS AND MOLDS 



301 



is in turn converted into alcohol by the Saccharomyces. If the fermenta- 

 tion product (as grape wine, apple cider, beer, porter, etc.) is exposed to 

 the air for a time, the Mycoderma aceti enters and at once begins to convert 

 the alcohol into acetic acid and we finally have vinegar. "Hard cider" 

 is simply apple wine in which the acetic acid fermentation has progressed 

 to an advanced stage. 



In the manufacture of the Japanese and Chinese rice wine (sake") 

 the maltose fermentation of the starch (in the rice grain) is brought about 

 by the AspergUlus oryza as already stated. The process of beer and 

 sake manufacture may be compared as follows: 



BEER. SAKE. 



. i. Material Used 



Carefully selected barley is cleaned in A good quality of rice is thoroughly 

 running water, then macerated in water washed in cold water, then softened by a 

 to induce germination. Rice, wheat and steaming process. No hops used, 

 other cereals may be added. Hops are 

 used. 



2. Diastase Fermentation. Malting 



During the germinating process a fer- .The steamed rice is spread on mats and 



ment or enzyme (diastase) is liberated inoculated with tha spores and hyphse of 



which converts the starch into saccharine Aspergillus oryza. This fungus liberates 



compounds. The ferment is unorganized an enzyme (disastase) which converts the 



(non-living) and is soluble in water. The starch into saccharine substances. The 



germinating and fermenting grain consti- enzyme produced by the fungus is soluble 



tutes the beer wort. in water. Fermentation takes place in a 



warm room. 



3. Alcoholic Fermentation 



The beer wort (Bierwiirze) is now ready The sake wort (mold) is prepared by mix- 

 to be acted upon by the yeast organis ns ing the steamed rice and fungus (.4. oryzce) 

 (Saccharomyces ceremsece) which enter from in vats. Yeast cells (Saccharomyces of 

 the air or which may be added in pure sake") enter from the air and cause alcoholic 

 culture. The yeast organisms convert the fermentation, converting the saccharine 

 saccharine substances into alcohol and substances into alcohol and carbonic acid 

 carbonic acid gas (CO 2 ). gas (CO 2 ). 



The diastase and the yeast ferments are The diastase ferment (produced by A. 

 both active during this process. oryzce) and the alcoholic ferment (Saccha- 



romyces) are active during the entire 

 process. 



4. Expressing, Cooling, Clarifying and Pasteurizing 



These processes are very closely similar in beer and sak6 brewing. The differences, 

 if any, are slight and pertain to modifications of methods employed by different manu- 

 facturers. Preservatives, as salicylic acid, may be added. Both beverages may be rein- 

 forced with alcohol. This is not generally done with seke" as the brewers declare that the 

 addition of foreign alcohol destroys the characteristic flavor or bouquet. 



