Wine, at a general average, contains about 20 per cent. of spirit or alcohol; when port wine is put into bottles, a slow fermentation continues to go on, and a crust of tartar is deposited similar to that described above, and it is the separation of this tartar which causes port wine to improve by age.
What are called British wines, are liquids mostly made by fermenting the juice of the fruits whose name they bear, as currant wine, gooseberry wine, &c.; but as the climate of this country is not favorable to the growth of grapes, or the spontaneous fermentation of their juice, the grape wine of England is very inferior to the foreign. The juice of any fruit required to make wine of, has to be fermented artificially; this is generally done by making it slightly warm, and floating on the surface a piece of bread soaked with yeast; the wines thus produced are very apt to become sour, and it is generally necessary to add brandy to preserve them. Many of the British wines sold in London are made of an impure weak spirit called “faints,” sweetened and flavored with various substances, as ginger, orange-peel, &c. and sell for ginger or orange wine.
VINEGAR.
Vinegar is produced by fermenting and exposing to the air any liquor which contains sugar, such as wine, infusion of malt, cyder, &c.; by the addition of yeast, this sets up a fermentation, by means of which the sugar in any of these liquors is converted, first into spirit, and afterwards into vinegar; this contains a certain quantity of acetic acid, which makes the vinegar sour. In warm countries, vinegar is made by simply exposing the poorer kinds of wine to the sun’s rays, when they ferment and become sour. In England, all the vinegar produced is made by fermenting wort made of malt, this is fermented for three or four days, and is then put into casks, with the bunghole left open for several weeks, or until it is thoroughly sour. In ordinary vinegar, there is about five or six parts only in the hundred of real acetic acid, but this acid, when pure, is so strong as to blister the skin when dropped on it; it is often extracted from vinegar for chemical purposes, and to smell too; for when scented, it constitutes aromatic vinegar. Vinegar, besides acid and water, contains a little unchanged spirit, much coloring matter, and some mucilage.
BOILER OR COPPER.
COOLING APPARATUS.