336 On the Cultivation of the Fitie, 



state the liquor is turbid, and every thinu; is mixed, cotj- 

 founded, agitated, &;c. ; filaments, pellicles, flakes, grapes, 

 and stones, float separately, and are pushed, expelled, preci- 

 pitated, and thrown up, till they at leuirth settle at the sur- 

 face, or are deposited at the bottom of the vessel. In this 

 manner, and by a series of intestine movement, there is 

 formed at the surface of the liquor a crust of greater or less 

 thickness, called by the French le chatenu de la vendaniie. 



This rapid movement and continual disengagement of these 

 aeriform bubbles considerably increase the volume of the 

 mass. The liquor rises in the vat above its primitive level. 

 The bubbles, which experie4ice some resistance to their vo- 

 latilisation by the thickness and tenacity of the ckupeav, force 

 a passage to themselves in certain points, and produce abun- 

 dant froth. 



The heat increasing in proportion to the energy of the fer- 

 mentation, an odour of spirit of wine is disengaged, and dif- 

 fused every where around the vat; the liquor assumes a darker 

 colour; and after several days', and sometimes even after a 

 few hours', tumultuous fermentation, the symptoms decrease ; 

 the mass resumes its former volume, the liquor becomes bright, 

 and the fermentation is almost terminated. 



Among the most striking phcenomena and the most sensible 

 effects of fermentation there are four principal ones which 

 require particular attention ; the production of heat, the dis- 

 engagement of gas, the formation of alcohol, and the colora- 

 tion of the liquor. 



I shall here speak of each of these phaenomena, according 

 to what we know of them with certainty from observation. 



1st, Production of Heat. — It sometimes happens in cold 

 countries, but particularly when the temperature is above 55 

 degrees, that the liquor put into the vat experiences no fer- 

 mentation, unless some means can be found to heat the mass. 

 This may be done by introducing into it warm must, stirring 

 the liquor strongly, heating the atmosphere, or covering the 

 vat with cloths. 



But as soon as the fermentation begins the heat acquires 

 intensity. Sometimes a few hours' fermentation is sufficient 

 to carry it to the highest degree. In general it is in the ratio 



of 



