30 THE GRAPE. 



(racemate of lime being less soluble than tartrate of 

 lime) ; and next, because cream of tartar is much 

 more easily soluble in water than double racemate of 

 potassa ; the first salt being soluble at 19, (66 2' E.,) 

 in 204 parts water, the latter in 180 parts. 



"Wines, therefore, which contain, besides tartaric 

 acid, a larger proportion of racemic acid, in conse- 

 quence of the presence of this acid deposit during 

 fermentation, (supposing an equal quantity of bases,) 

 a larger amount of lime salt and potash. They are, 

 therefore, sweeter, and if red wines, darker coloured 

 than wines which contain only tartaric acid. At the 

 same time this result depends entirely on the quan- 

 tity of bases present at one time, for if these are 

 less in wines containing racemic than in those in 

 which tartaric acid is found, more free acid may be 

 dissolved in the former, and the wine will then be 

 redder coloured, and less sweet tasted. 



THE SUGAR. 



The sugar which exists in grapes is called " grape 

 sugar," although this name no longer denotes a par- 

 ticular kind of sugar. By a process to be mentioned 

 hereafter, from 4 parts sugar from grape juice, only 3 

 parts can be obtained solid, and 1 part as fruit sugar. 

 The grape juice is boiled with chalk, in order to 

 saturate the free acids, the liquid is filtered, and 

 the precipitate washed. The liquid matters are mixed 



