VINEGAR is a liquor of an agreeable smell, a pleasant and strongly acid taste, and of a hue varying from light-red to brown-straw colour; and is prepared by fermenting any substance or compound which has already undergone the spiritu ous fermentation. Vinegar, therefore, may be made immediately from any wine, malt liquor, cyder, &c. ; or from the juice of the grape and other fruits ; from infu sion of malt, or any saccharine liquid, through the intermedium of vinous fer mentation. Both these methods are ac tually practised with complete success. To make vinegar out of a liquor contain ing suitable materials, it is only necessa ry, 1st, to allow some access of air to the vessel in which it is kept ; and 2d to keep it in a temperature rather higher thin that of the atmosphere in this climate, that is to say, about 75° to 80°. It is also al most essential, where a liquor already fer mented is employed, to add a portion of yeast, or any other ferment ; for though any fermented liquor, if kept in a mode rate temperature in an open vessel, will spontaneously run sour, or become chang ed to vinegar ; this change is too gradual to produce this acid in perfection, and the first acetified portion turns mouldy before the last has become sour : but where the substance employed has not yet under gone fermentation, the whole process of the vinous and subsequent acetous fer mentation will go on uninterruptedly with the same ferment which at first set it in action, which happens, for example, in the making vinegar from malt, or from sugar and water. In this country vinegar is chiefly made from malt. The follow ing is the usual process in London : A mash of malt and hot water is made, which, after infusion for an hour and a half, is conveyed into a cooler, a few inches deep, and thence, when sufficient. ly cooled, into large and deep fermenting tuns, where it is mixed with yeast, and kept in fermentation for four or five days. The liquor, (which is now a strong ale without hops) is then distributed into smaller barrels, set close together in a stoved chamber, and a moderate heat is kept up for about six weeks ; during which the fermentation goes on equally and uniformly till the whole is soured. This is then emptied into common barrels, which are set in rows (often of many hun.
dreds) in a field in the open air, the bung. hole being just covered with a tile, to keep off the wet, but to allow a free ad mission of air. Here the liquor remains for four or five months, according to the heat of the weather, a gentle fermenta tion being kept up till it becomes perfect vinegar. This is finished in the following way: Large tuns are employed, with a false bottom, on which is put a quantity of the refuse of raisins, or other fruit, left by the makers of raisin and other home made wines, called technically rape. These rape•tuns are worked by pairs ; one of them is quite filled with the vinegar from the barrels, and the other only three-quarters full, so that the fermenta. don is excited more easily in the latter than the former ; and every day a portion Ofthe vinegar is laded from one to the other, till the whole is completely finish ed, and fit for sale. Vinegar, as well as fi•it•wines, is often made in small quanti. City fir domestic uses, and the process is by no means difficult. The materials may he either brown sugar and water alone, or sugar with raisins, currants, and especial ly ripe gooseberries : these should be Mixed In the proportions which would give a strong wine, put into a small bar rel, which it should fill about three fourths, and the bunghole very loosely stopped. Some yeast, or, what is better, a toast sopped in yeast, should be put in, and the barrel set in the sun in summer, or a little way from a fire in winter, and the fermentation will soon begin. This should be kept up constant, hut very mo ilerate, till the taste and smell indicate that the vinegar is complete. It should be poured off clear, and bottled carefully; and it will keep much better if it is boiled for a minute, cooled, and strained before bottling. Vinegar contains a considera of colouring extractive mat ter, from which it can only be freed by distillation ; the process of which will be clearly understood by a reference to the article DISTILLATION. See also Acetic acid. When vinegar is long kept, especially exposed to the air, it becomes muddy, acquires a mouldy, unpleasant smell, loses its clear red colour and all its properties, and finally, is changed to a slimy mucilage and water.