443 
ACIDS. 
Malt Vinegar. 
In this country vinegar is usually made from malt. By 
mashing with hot water, 100 gallons of wort are extracted, 
in less than two hours, from six bushels of malt. When the 
liquor has fallen to the temperature of 75° Fahr., four gal 
lons of yeast are added. After thirty-six hours it is racked 
off into casks, which are laid on their sides, and exposed, 
with their bung holes loosely covered, to the influence of 
the sun in summer; but in winter they are arranged in a 
room heated by stoves. In three months this vinegar is 
ready for the manufacture of sugar of lead. 
To make vinegar for domestic use, however, the process 
is somewhat different. The above liquor is racked off into 
pairs of casks placed upright, having a false bottom pierced 
with holes fixed a foot from their bottoms. On this a 
considerable quantity of rape, or the refuse from the makers 
of British wine, or otherwise a quantity of low-priced raisins 
is laid. The liquor is pumped into the other barrel every 
twenty-four hours, in which time it has begun to grow 
warm. Sometimes, indeed, the vinegar is fully fermented 
without the rape, which is added, towards the end, to 
communicate flavour. 
Vinegar is made at Ghent, in Flanders, from beer; in 
which the following proportions of grain are found to be 
most advantageous : 1880 pounds of malted barley ; 700 of 
wheat; and 500 of buck wheat. These grains are ground, 
mixed and boiled, along with twenty-seven barrels of river 
water, for three hours; eighteen barrels of good beer for 
vinegar are obtained. By a subsequent decoction, more 
fermentable liquid is extracted, which is mixed with the 
former. The whole brewing yields about 750 gallons, Eng 
lish measure, of vinegar. 
Common vinegar has, sometimes, sulpnuric acid fraudu 
lently mixed with it, to give strength. This adulteration 
may be detected by the addition of a little chalk. With 
pure vinegar, lime forms a limpid solution ; but with sul 
phuric acid, a white insoluble sulphate. Muriate of barytes 
is a still nicer test. Vinegars are allowed, by the English 
laws, to contain a little sulphuric acid, but the quantity is 
frequently exceeded. 
Copper is discovered in vinegar by adding more ammonia 
water than is necessary to saturate it, as a fine blue colour 
is produced ; and lead is discovered by sulphate of soda, 
hydro-sulphurets, sulphuretted hydrogen, and gallic acid,