FERMENTATION. 247 



in the fermentation, are either precipitated to the bottom, or 

 deposited upon the sides. All the methods adopted for clar- 

 ifying wine are founded upon this principle. The mucilage, 

 tartar, and extractive matter which must holds in solution, 

 are only suspended in well-fermented wine, and are gradual- 

 ly deposited from it. The burning of brimstone in the casks 

 facilitates the formation of the deposit, and racking sepa- 

 rates the deposited matter from the liquor. By the addition 

 of isinglass or any similar substance to wine, all the particles 

 which remain suspended in it are seized and united together, 

 and can thus be removed. 



All these operations tend to free the wine from foreign 

 substances, and to prevent it from becoming changed, and at 

 the same time to preserve all the taste and good qualities 

 which belong to it. The red wines lose a part of their col- 

 oring matter by age, and, if the wine has been well clarified, 

 this change can be accelerated by exposing bottles filled 

 with it to the heat of the summer's sun. In this case the 

 coloring matter is precipitated in pellicles, and the wine be- 

 comes of the color of an onion skin, but undergoes no other 

 change : I have seen this done in experiments upon the best 

 wines of Languedoc. 



When wine is put into new casks, it dissolves a portion 

 of the tannin and extractive matter contained in the wood, 

 and is thus colored and decomposed, especially if the wine 

 be not very strong. The liquor in this case acquires what 

 is called the taste of the cask. The color which brandy 

 receives in the cask is from these same principles. To 

 obviate this inconvenience, the inside of the hogsheads 

 should be charred ; the wine will then be preserved free from 

 alteration. 



The most common degeneration of wine is its becoming 

 sour, by which it is converted into vinegar : this does not, 

 however, take place if the wine has been completely freed 

 from the mucilage and extract contained in the must, but 

 fermentation is seldom thorough enough to disengage entire- 

 ly, and render insoluble these principles, especially if the 

 grapes are not well ripened. 



This degeneration may be retarded, and even prevented^ 

 by keeping the liquor in closely stopped casks set in a cool 

 place, where they will be free from motion, as every shake 

 of the cask mixes again with the wine the substances which 

 have been precipitated from it. 



The acidification or acid degeneration does not take place 



