214 GKAPE CULTURE AND WINE-JIAKING. 



YII. 

 CLARIFYING WINES. 



In most wines clarification results from tlieir own action, as 

 the yeast parts settle down as soon as the fermentation is over. 

 Especially is this the case with dry wines, i. e., such as have per- 

 fectly fermented out, and these need no artificial help. 



It is, however, different with sweet and oily wines, in which the 

 still undissolved sugar contains a great deal of yeast in an unde- 

 composed state ; and the slimy and extractive parts do not easily 

 settle. With these it is necessary to add a slimy body, that mixes 

 itself with them, then coagulates, and in this state absorbs all those 

 parts. 



Such substances are animal jelly and albumen {ivhite of an egg). 

 They arc both dissolved in water, and stirred into the wine. The 

 gelatinous matter coagulates, in conjunction with the tannic acid, 

 into an insoluble substance. Consequently, it can only be used 

 for clarifying such wines as contain tannic acid ; or, if not, the}' 

 must be made to contain it by a decoction of oak shavings or 

 catechu poured into it, or by putting the shavings themselves 

 into the cask. The white of an egg also forms a similar insolu- 

 ble connection with the tannic acid, but coagulates by heat or 

 strong spirit, and satiates a small portion of the vinous acids. It 

 may, therefore, be used for wines that have no such tannic acids, 

 if they are only strong in spirit. The wines that are to be clari- 

 fied are usually not sulphurized. 



The most convenient time for the operation are cool, pleasant 

 days. Old wines are closed up after being mixed with the sub- 

 stance ; young ones, generating much carbonic acid, are left with 

 a small opening during the first day to allow this to escape. 



The white of the egg is best stirred up with water before add- 

 ing it to the wine. Three eggs will generally suffice for about 

 160 bottles of red wine. If not, it will be better to repeat the ex- 

 periment than to take at once a greater number. In young wines 

 a little salt may be safely added. 



The clearing by isinglass is done by beating this material first 

 with a hammer, then tearing it into small pieces and putting them 

 into a vessel containing wine. This is poured off in about eight 

 hours, and new ones added. After twenty-four hours a jelly will 

 be formed, to which hot water must be added ; then the mass is 

 kneaded with the hands to accelerate the dissolution, strained, 

 and beaten, with the addition of a little more wine, for about a 

 quarter of an hour. In this condition it is mixed with the wine 

 in the cask. One litre of isinglass will sufiice for about 240 or 

 260 bottles of white wine. In Germany one half to two ounces 

 of it are taken, according to circumstances, to one fuder ; in France, 



