Rena Wells, age 12, of Casper, Wyo., for her question:
WHAT IS VINEGAR AND HOW IS IT MADE?
Vinegar is a sour liquid used for seasoning foods. It is also used in pickling and processing fruits, vegetables and meats. The name "vinegar" is from the French word "vinaigre," which means "sour wine." But many kinds of vinegar are not made from wine.
Cider vinegar is made from the juice of apples. Fermentation changes the fruit sugar in the juice into alcohol and carbonic gas. The gas evaporates, or passes off, leaving the alcohol and fruit flavors, or "esters."
Oxidation changes cider into vinegar. The oxygen in the air comes in contact with the alcohol in the cider and, with the aid of the vinegar bacteria, the alcohol changes into vinegar.
Two general methods of making vinegar are the slow, natural process and the quick process.
The slow process may take from one to two years, depending on temperature and access to air. The fermented liquid may be kept in a special oak barrel or cask with holes to permit air circulation. It should be only about four fifths full, so there is ample air space.
In the quick method, the fermented cider is circulated continuously through vats called generators. The generators are filled with such porous material as corncobs, rattan shavings or coke. Lukewarm, strong cider vinegar is circulated through the porous material for 24 to 48 hours. Then the fermented cider is fed into the top of the generator through a spray.
The cider is split into drops and each drop is brought into contact with currents of air that enter through holes near the bottom of the generator. An efficiently run generator converts 1,000 to 2,000 gallons of cider into vinegar in 48 to 72 hours.
During the process of converting fermented fruit juices into vinegar, particularly cider vinegar, a slimy scum called "mother of vinegar" (bacterium xylinum) forms. Manufacturers try to prevent the formation of vinegar mother. It slows down the circulation .of air.
Four percent is the legal minimum acid strength for commercial vinegar.
Vinegar is just the result of the chemical changes known as fermentation. A dilute or weak alcohol is the raw material from which all vinegar is made. The alcohol may be produced from the fermentaton of the juice of any fruit, berry or even melon. Malt vinegar is made from cereals.
Vinegar can also be made from sugar solutions, such as molasses, sugar syrup or honey.
The flavors, colors and odors of various kinds of vinegar come from the substances from which they are made. Cider vinegar has an applelike odor and is brown or yellow.
Distilled vinegar is clear and has no flavor, other than acidity. Most of this vinegar is made from molasses. But some is made from whey, which is the liquid part of milk.