WINE MAKING. 433 



the second fermentation has ceased, the com 

 pleted wine may be drawn off and bottled, 

 when it is new wine, and ready, as such, for 

 use. 



This, in brief, is the history of wine making 

 in its most simple form: a plain statement of 

 the processes without any attempt at explana 

 tion by theory ; and a general statement of 

 what is known of the chemistry of wine making 

 is quite as simple. The sugar of the grape, by 

 a chemical action called vinous fermentation, is 

 converted into alcohol, setting free carbonic 

 acid, which escapes into the air in the form of 

 gas, while the former remains dissolved in the 

 water of the grape with the other constituents, 

 chiefly unchanged. What fermentation itself 

 is, is quite another question. If the vinous 

 fermentation were perfect, every one hundred 

 parts of the sugar would be converted into 

 51*11 parts of alcohol and 48 89 parts of car 

 bonic acid. The action of the ferment depends 

 for its force upon the rapid absorption of the 

 oxygen of the air, without which it can not 

 take place. 



Two modes of fermenting are practiced, above 

 and below. In the first, the cask is kept full, 

 so that the yeasty parts flow out at the bung. 



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