GRAPE PRODUCTS 253 



grape pomace is built up into a "cheese" by the use of cloths 

 and racks variously arranged. The "cheese" is then put under 

 heavy pressure from which the juice or "must" is quickly ex- 

 tracted. 



The third stage is fermentation. The "must" is carried 

 from the press into open tanks or vats which hold from 500 to 

 5000 gallons or even more. The yeast cells which cause 

 fermentation may be introduced naturally on the skins of the 

 grapes; or in many modern wineries the "must" is sterilized 

 to rid it of undesirable micro-organisms and a "starter" of 

 "wine-yeast" is added to start the fermentation. Yeast 

 organisms attack the sugar and must, breaking it up into alco- 

 hol and carbonic acid gas, the latter passing off as it is formed. 

 When active fermentation ceases, the new wine is drawn from 

 the pomace and is put into closed casks or tanks where it 

 undergoes a secondary fermentation, much sediment settling 

 at the bottom of the cask. To rid the new wine of this sediment, 

 it must be drawn off into clean casks, an operation called 

 "racking." The first racking usually takes place within a 

 month or six weeks. A second racking is necessary at the end 

 of the winter and a third is desirable in the summer or fall. 



The fourth stage is the aging of the wine. Before aging 

 begins, how^ever, the wine usually must be rendered perfectly 

 clear and bright by "fining." The materials used in fining are 

 isinglass, white of egg or gelatine. These, introduced into the 

 wine, cause undissolved matters to precipitate. The wine is 

 now ready for bottling or consumption. INIost wines acquire a 

 more desirable flavor through "aging," a slow oxidation in the 

 bottles. 



Champagne. 



When champagne wines have gone through their first fermen- 

 tation, they are racked off into casks to age until their quality 

 can be ascertained, after which a blend of several different 



