This section is from the book "The Manufacture Of Liquors, Wines, And Cordials, Without The Aid Of Distillation", by Pierre Lacour. Also available from Amazon: Manufacture of Liquors, Wines, and Cordials, Without the Aid of Distillation.
This process of manufacturing acetic acid, or pure vinegar, has superseded that of all others, both in Europe and America. This is owing to the many advantages that it presents. Among the most prominent may be noticed its rapid formation or acetification. The rationale of the conversion of whiskey and water into vinegar may be necessary to explain.
Liebig supposes that it takes place in consequence of the formation of a new substance, called aldehyd, into which the alcohol is changed by the loss of a part of its hydrogen. The alcohol, consisting of four equals of carbon, six of hydrogen, and two of oxygen, loses two equals of hydrogen through the influence of the atmosphere, and becomes aldehyd, composed of four equals of carbon, four of hydrogen, and two of oxygen. This, by the absorption of two equals of oxygen, becomes four equals of carbon, four of hydrogen, and four of oxygen, that is, hydrated acetic acid. Thus the conversion of alcohol into acetic acid, consists in, first, the removal of two equals of hydrogen, and afterwards the addition of two equals of oxygen. Aldehyd is a colorless, very inflammable, ethereal liquid, having a pungent taste and smell. Its density is 0.79. It absorbs oxygen with avidity, and is thus converted into acetic acid, as just described. Its name alludes to its relations to alcohol - Alcohol dehydrogenated.
Having stated one of the most important considerations in the economy of the manufacture of vinegar, viz. its rapid formation, the minor considerations will be briefly noticed. And probably this could not be more effectually performed than by contrasting the two processes.
Take a well arranged vinegar manufacturing establishment of the old style, one that is capable of turning out forty barrels of vinegar daily, and from seven to ten operators will be necessary to conduct the process, to say nothing of the appurtenances, in the form of vats, tuns, cisterns, coolers, heaters, hydro lusters, thermometers, kettles, boilers, furnaces, etc, etc, and to fully comprehend the amount of space (house room), requisite for these fixtures, to manufacture forty barrels of vinegar daily, it will be necessary to remind the reader that the vinegar that was sent into the market to-day, has been undergoing the process of manufacture, or of acetification, for several months.
By the proposed method, forty barrels of vinegar can be manufactured daily, requiring only two operatives and two large generators, or a series of small ones. The quantity of vinegar manufactured will be proportioned to the capacity of the generators. The generator that acetifies ten thousand gallons daily, is governed by and acts upon the same principle as the generator of the capacity of ten gallons,
Unlike the old process, the new is unaffected by external influences or chemical changes. Neither is its management invested in a chemical knowledge the generators being once charged, the labor for the operatives becomes entirely mechanical.
Persons desirous of engaging in this business, and from a want of confidence in their abilities, and fearful that the directions here prescribed may be deficient in all of the details of the process - details that ore necessary to success - that it would prevent them from engaging in the business; and in view of this the whole plan can be tested at a trifling cost, on a small scale, by the use of a keg, arranged on the same principle that the generators are. This experiment will be required, as proof of favorable results, which will inspire confidence in the investment.