VINEGAR-MAKING. Vinegar is a dilute acetio acid obtained by the vinous fermentation. [FERMENTATION.] In countries which pro duce wine, vinegar, as its name imports, is obtained from the acetous fermentation of wine ; but in this country it is usually procured from malt, and the process employed resembles the first stage of the brewer's operations. •[llazwzaro.] The malt is ground and mashed with hot water. The wort, after being cooled, is transferred to the fermenting tun, where, by the addition of yeast, it undergoes the acetous fermenta tion; and when this is over, the liquor is transferred to small vessels, which are kept warm by means of a stove : in this it remains for a shorter or longer period, according to the temperature of the stove and the strength of the liquor. The process of acetification is assisted by introducing into the casks with the wort what is called rape, the residuary fruit which has served for making domestic wines, or has been preserved by the vinegar-maker from one process to another in his own factory. The use of the rape is to act as an acetone ferment, and thus induce sourness in the wash, it being well impregnated with vinegar and continually kept sour. Acetification is sometimes carried on by transferring the wort, after it has undergone the vinous fer mentation, into casks, the buogholes of which are left open and loosely covered with tiles ; the casks are then exposed for a long time to the air. But the use of stoves has greatly superseded this mode, and has abridged the time of the operation and rendered it less liable to failure. The vinegar, after it has reached its greatest degree of sourness, is rendered clear and fit for use either by subsidence or the employment of isinglass. The manufacturer is allowed by act of parliament to mix of its weight of sulphuric acid with vinegar ; and what is termed by the Excise proof vinegar contains 5 per cent, of real acetic acid.
Vinegar may be prepared in small quantities from the fermentation of a solution of sugar mixed with yeast ; or it may be obtained by the fermentation of various fruits : thus, the juice of good apples contains a sufficiency of sugar to afford tolerably good vinegar without any addition.
In France, vinegar is made from poor wine, and there are two kinds: the white, prepared from white wine ; and the red, by the acetification of the red wine. These are finer flavoured and somewhat stronger than the malt-vinegar of this country.
Vinegar-works in this country are but few in number ; they require a large amount of space and the investment of much capital. There are about half-a-dozen of them in the metropolis. At most of those in this country, as has been said, malt is the kind of grain employed ; but the vinegar-maker holds himself free to the use of unmalted grain, if price and other circumstances should render it desirable, or saccha rine substances instead of grain. From whatever substances the gyle
is produced, the conversion of it into vinegar is managed nearly in the same way. Where the rape is not to be procured easily, the vinegar maker uses wood-shavings, straw, or even tanuera' spent bark ; but the rape is so far preferable, that a large expenditure is sometimes incurred to obtain a sufficient quantity : hence the advantage of carry ing on the " British wine " manufacture and the vinegar manufacture in the same establishment (which is sometimes done); refuse raisin stalks and skins result from the making of raisin-wine. Vinegar is known by certain numbers, such as Nos. 18, 20, 22, and 24 ; these originally represented, it is supposed, the number of pence per gallon at which the vinegar was sold ; and although the price no longer agrees with the numbers, they have been retained as designations for different kinds or strengths of vinegar. Tho quantity made in the United Kingdom is not now known ; some years ego it was about 3,000,000 gallons annually.
It may be well to remark that, in country districts, much vinegar, but of inferior quality and insipid flavour, is made by the aid of the singular substance known as the vinegar-plant. This substance is rather a scum than a plant. In Staffordshire, a vinegar-plant is thus produced :—About a quarter of a pound of sugar and half a pound of treacle are put into three quarts of water ; the solution is simmered, poured into a jar, covered up, and kept in a warm corner for six weeks an inferior kind of vinegar is formed, and on the top of it Is a scum, with very much the appearance of tripe constituting the so-called vinegar plant. Vinegar can thus be made from a sweet liquor alone ; but when a vineg.ir-plant is once produced, it greatly quickens the process of vinegar-making, without materially altering the proportions of the other ingredients. A gallon of vinegar is thus made at a cost of about sixpence. During the process the vinegar-plant thickens, by the formation of a new layer on the under surface ; tho two layers may easily be separated, and each will be available for a further process of vinegar-making, and this three or four times over. The substance is a kind of fungus, whitish in colour, semi-transparent, jelly-like, and sometimes an inch in thickness. In some country places strong pickling vinegar is made by cottagers, by mixing cowslip flowers and stalks with sugar and water, adding a little yeast, closing it up, and allowing it to remain in a warm place for several weeks.