Researches on Wines and other Fermented Liquors. 43 
Acetic and Carbonic Aciils—Acetic acid is often found in the 
wines from northern countries, and in altered wines it is formed at the 
expence of the alcohol. Almost all wines, however, exhibit the 
acid reaction. In champaigne, it is owing to free carbonic acid, but 
in others it is due to the bitartrate of potassa. The effervescence 
which is observed on adding carbonate of potassa to wine and the 
subsequent precipitation, are the results of the action of this excess 
of tartaric acid, and the consequent liberation of a portion of tartrate 
of lime which this salt most generally contains. 
Malic Acid.—It has been frequently stated, that wine contains 
malic acid, anda malate of lime is said, by Chaptal, to be formed by 
the addition of lime water to wine ;—an opinion which seems also to 
be countenanced by Mr. Brande. But the existence of this acid is 
rendered doubtful, if not disproved, by the fact that an insoluble pre- 
cipitate results, as well from the addition of ammonia or potassa, as of 
lime. Now the malates of these alkalies are very soluble, and hence 
we may more safely ascribe the precipitate thrown down in all these 
cases to the saturation of the excess of tartaric acid contained in the 
bitartrate of potassa, by which means the insoluble tartrate of lime, 
which is usually combined with it, is liberated. 
Vegetable Albumen.—Grapes, according to Berzelius, contain a 
small portion of this substance, which he has described in the fifth 
volume of his elaborate treatise on chemistry. In examining a spe- 
cimen of American wine, which was said to be the pure juice of the 
grape, I found, that when evaporated to about one eight of its bulk, 
upon adding a portion of alcohol, there was a deposit of a tough dark 
colored matter, soluble in water and in solution of ammonia, but in- 
soluble in sulphuric acid. In these respects, it agrees very well with 
the description of vegetable albumen given by Berzelius. A portion 
of pure madeira when treated in the same manner, yielded a bulky 
white precipitate of saline matters. 
Sulphate of Potassa.—The presence of sulphuric acid in wines is 
distinctly shown by the dense precipitate which results from the ad- 
dition of muriate of barytes. Iam not aware that any other ingredi- 
ent would produce this effect, except carbonic acid, but the carbonate 
would be soluble in muriatic acid, which is not the case with the pre- 
cipitate in question. 
Tartrates of Potassa and of Lime.—The bitartrate of potassa is 
one of the most abundant of the solid ingredients of wine, and the 
tartrate of lime, as has already been remarked, is generally associated 
