46 THE GRAPE . 



in wine is by no means large, and, without asserting 

 that they are yielded entirely by the fat found in the 

 juice and stones, it appears to me that the quantity of 

 fat existing in these is more than sufficient to produce 

 the fat acids of wine. 



This point is of special importance, because the fat 

 acids play a principal part in wine, and those wines in 

 which the skins and oleaginous stones have been 

 allowed to ferment, contain as a rule more fatty oil 

 than those obtained from grape juice alone. 



GE APE- STALKS. 



The stalks deserve our attention for a moment, 

 since they, too, are allowed to ferment. 



They, like the skins, and especially the stones, have 

 a sharp astringent flavour. 



If treated with water, the addition of a salt of oxide 

 of iron indicates a considerable portion of tannic acid. 

 The other ingredients are of no value to us as regards 

 our special objects. 



Tannic acid may therefore be obtained from the 

 skins, stones, or stalks, but not from the juice itself. 



