From the Student's Reference Work Vol. 2 by Charles Belden Beach ©1893
Vinegar is a weak form of acetic acid, generally produced by fermentation of the juices of fruit, and varying in flavor according to the material from which it is made. In Great Britain vinegar is usually made from malt, which is fermented in casks, which are three-quarters full, with holes for the entrance of air. They are kept at a
certain temperature (about 70°), and the process may take weeks or months. The vinegar is then filtered and cleared. What is known as the German rapid process consists in pouring the malt or fermented wort in a shower on to shavings in a cask, and drawing off the liquid and pouring it in again, repeating the process until the vinegar has the right degree of acidity. Wine vinegar is largely made in France, and other wine producing countries from the poorer wines, and the lees or settlings of the wine vats. It is white or red, according to the color of the wines used. In the United States cider vinegar is considered the best, and the process is essentially the same as that used in making malt vinegar, warmth and exposure to the air being the two necessary conditions. Homemade vinegar is often produced by putting what is known as the vinegar plant or "mother "into a weak solution of sugar or molasses. The vinegar plant is found in old vinegar barrels and is a fungus growth similar to the yeast plant. The word vinegar means sour wine. See Fermentation.