246 CHYMISTRY APPLIED TO AGRICULTURE, 



changes of temperature, which are unfavorable to fermenta- 

 tion, the head of the liquor is prevented from becoming sour, 

 and at the same time a constant and equable heat is kept up 

 during the operation. Should the fermentation appear to re- 

 lax, the liquor must be stirred with a bough, so as to mix 

 with it the leaven which has formed upon the top, and by 

 this a new impulse will be given to the process. Good ef- 

 fects arise also from keeping a bough of the vine immersed 

 in the liquor by means of boards or a string. 



The ancients carefully separated all the various juices 

 which they could obtain from grapes, and fermented them 

 singly : the first, which was procured from the ripest grapes 

 by the slightest pressure, furnished their finest wines, called 

 by them protopon, mustum sponte defiuens antequam calccn- 

 tur uvcB. Baccius describes this process as practised by the 

 Italians, thus : Qui primus liquor, non calcatis uvis, dejluit, 

 vinum efficit virgineum, non inquinatum facihus ; lacrymam 

 vacant Itali ; cito potui idoncum, et valde utile. 



When the wine has fermented sufficiently in the vat, it is 

 put into hogsheads, and there undergoes an insensible fer- 

 mentation, which completes the operations ; by being kept 

 undisturbed it settles and becomes clear. 



In those countries where grapes arrive at perfect maturity, 

 wine can be kept in the vat in which it is fermented, with- 

 out any danger of alteration ; and this is done in most of the 

 southern cantons ; it is however necessary, in this case, that 

 the joinings of the boards with which the vats are covered 

 be plastered over with mortar, that the air may not gain ad- 

 mittance. 



Wine makes better when in large quantities than when 

 divided in casks ; but in those countries where the grapes 

 contain less sugar, and where, after fermentation in the vat, 

 the wine still contains much mucilage, if putting it into 

 casks is delayed, the fermentation will very soon be followed 

 by the second, and the product of this last is vinegar : the 

 existence of alcohol and mucilage is sufficient to occasion 

 this change. 



The casks which receive the wine from the vat should be 

 arranged in a place where the temperature is cool and uni- 

 form, and where they will not be exposed to being shaken or 

 jolted. 



When fermentation has not been completed in the vat, 

 it is continued in the casks, and all the principles con- 

 tained in the must, which are not susceptible of concurring 



