FERMENTATION. 57 



and was repeated at Johannisberg in 1846 with 

 great success, Prince Metternich having placed 6 

 casks, each containing 1200 bottles, at the disposal of 

 the experimenters. An aperture of six square inches, 

 covered with a piece of coarse canvas, was suffi- 

 cient. 



The wine which fermented in them was of a better 

 quality than that which underwent the same process 

 in a cask which was closed and only provided with a 

 glass tube for the passage of carbonic acid. Experi- 

 ments of the same kind, tried by Crasso,* were equally 

 successful. 



But in other experiments, made with white wine, 

 the wine in open casks appeared to lose in aroma ; 

 doubtless, therefore, much depends on the kind of 

 wine. 



Prom these experiments we may, however, deduce 

 the general principle, that wine placed in open casks 

 requires a lower temperature, while for that put into 

 closed vessels a greater degree of heat is necessary 

 during fermentation. "Wines containing a great deal 

 of sugar may therefore be allowed, with advantage, 

 to ferment in closed vessels, whilst those less rich in 

 saccharine contents may be left in open casks, pro- 

 vided the temperature be low and equable. 



Many, however, have opposed this opinion of Lie- 

 big, and Schubert t in particular attacked it, stating 



* Liebig's Ann. Bd. 59, s. 360. 

 + Erdmann's Journ. Bd. 36, s. 45. 



