240 
VITIS VINIFERA. 
wine. It is then put into casks, and subsequently into bottles, in 
both of which an imperceptible fermentation still goes on, and which 
in fact is. not completed until the wine attains the utmost limit of its 
age, and passes into the acetous fermentation. The saccharine matter, 
the gluten, and the vegetable acid, are the principles of the must, 
which are essential for the production of wine ; and the strength and 
quality of the wine, depend on the quantity of the first in particular, 
and on the manner of conducting the fermentation ; when the sugar 
is in too great quantity, and not completely decomposed, or the fer- 
mentation is checked, the wine retains a sweet taste ; this is the case 
with Malaga, Frontignac, Tokay, Vino Tinto, the Malmsey wines of 
the Greek islands, and some others. A more proper proportion of 
sugar, and perfect decomposition, with a brisker fermentation, ren- 
ders the wine strong and spirituous, as Port, Sherry, Madeira, and 
Marsala. If the quantity of sugar be small, and at the same time a 
deficiency of tartar in the must, a thin and weak wine is produced j 
of this nature are Claret, Hock, Rhenish, IMayne, Barsac, &c. When 
wine is bottled early, it becomes brisk and sparkling, which it owes 
to the presence of carbonic acid gas, as we see in Champagne ; when 
the fermentation has been conducted on the skins of the grapes, the 
wine is rendered rough and astringent ; and if the black or purple 
grape is used in this way, we have what is termed a red wine : to 
this circumstance, Port, Claret, and Burgundy, owe their dark 
colour; but if the juice only be fermented, white wines may be pro- 
duced from coloured grapes. Bitter almonds, orris root, and some 
other substances are used as flavouring ingredients to the more fully 
fermented wines. Wine that has been too long fermented before it 
is put into the casks, is very apt to run into the acetous fermentation, 
when white lead, litharge, and deleterious oxides of lead are used to 
correct the acidity, forming, according to Fourcroy, a soluble, triple 
salt ; the aceto- tartrate of lead, by uniting with the acetic and tar- 
taric acids in the wine. Wine thus adulterated is apt to produce 
cholic, and other bad effects, in those who drink it ; the presence of 
lead in wine, may be detected by dropping into it a few drops of 
the prussiate of potass, when a whitish precipitate will take place. 
Arsenic and corrosive sublimate have sometimes been used in the 
fining of wines, and Port wine is very frequently adulterated by the 
admixture of Cyder, logwood, sloes, and other ingredients.* Nitrous 
ether is sometimes employed to perfume wines. 
* Tlie manufacturing of Port wine from Cjder, &c. is a regular branch of business 
in the Island of Guernsey. 
