20 ON THE ART OF MAKING WINE* 



cially suspended, by separating the wine already 

 produced from the ferment with which it is mix- 

 ed. The operations in use for this end, consist in 

 decanting, in clarifying by means of glue or al- 

 bumen, or in the use of certain chemical substan- 

 ces which decompose the leaven ; processes which 

 I must consider more at length hereafter. From 

 this view, it will be easily deduced, that sweet 

 wines cannot turn sour, because their leaven has 

 been expended. Another remark of equal im- 

 portance may also be deduced, that all wines will 

 have this tendency, if the whole of tne sugar of 

 the fluid has been converted, and if at the same 

 time care has not been taken to separate com- 

 pletely the leaven which may remain in them. 

 Hence the necessity of fining wines for their pre- 

 servation, as well as their beauty. It will also be 

 apparent, that if any fluid to be fermented, is of 

 such quality, that the leaven predominates over 

 the sugar, it will be necessary to stop the process 

 by chemical means, to prevent the occurrence of 

 the acetous stage, which would otherwise take 

 place. 



I have already stated, that both the malic and 

 the tartarous acids take a share in the process of 

 fermentation. Where the former naturally pre- 

 dominates, as in apples and pears, the produce is 

 cider or perry ; where it abounds in the juice of 

 the grape, it is supposed to lead to bad qualities in 

 the wine. The practice of liming wine vats, and. 



