Impure Dilute Acetic Acid, Prepared by Fermentation of Cider, Malt, or Wine.
Acetum Britannicum. — Common British made Vinegar, from infusion of malt. Density, 1006 to 1019.
Acetum Destillatum. — Distilled Vinegar.
Acetum Gallicum. — French Vinegar ; density, 1014 to 1022.
Acetum Vini. — Wine Vinegar. — Impure Dilute Acetic Acid.
History. — Sugar and water, and all saccharine vegetable juices, infusion of malt, wine, cider, and all liquors susceptible of vinous fermentation, may be converted into vinegar, by being exposed to a temperature between 75° and 90° F. with access of air, in which they undergo an action called acetous fermentation, and which is developed under a microscopic fungus influence, termed torula aceti. The several changes which occur during this fermentation, are included in the term acetification ; during the progress of which, heat is disengaged, the liquid becomes turbid, and filaments are formed, which move in numerous directions, and finally, the liquid becomes transparent, with a pultaceous deposit of the filaments, its alcohol has disappeared, and vinegar now occupies its place.
This change is supposed to take place, in consequence of the formation of a new substance called Aldehyd, the result of the loss of a part of the oxygen of the alcohol. Alcohol consists of four equivalents of carbon, six of hydrogen, and two of oxygen, through the action of the atmosphere, it loses two equivalents of hydrogen, and becomes aldehyd. This, absorbing two equivalents of oxygen, becomes hydrated acetic acid, consisting of four equivalents each of carbon, hydrogen, and oxygen. Aldehyd is an ethereal fluid, very inflammable, colorless, with a pungent taste and smell ; its density is 0.79. It absorbs oxygen with avidity. Its name has reference to its character, alcohol dehydrogenated. Aldehyd resin, a soft, light-brown mass, giving a nauseous soapy smell when heated to 212°, and is formed by decomposing the aqueous solution of aldehyd by caustic potassa.
Different liquors are employed in the manufacture of vinegar, in different countries ; in wine countries, wine is used; in Britain, infusion of malt ; in the United States, cider is principally used. The cider is placed in barrels with their bung-holes open, and which are then exposed to the heat of the sun, during summer, and the acetification is perfected in about two years. This fermentation must be watched during its progress, and as soon as the vinegar is formed, it must be racked off into clean barrels, otherwise it will become spoiled by running into the putrefactive fermentation.
Vinegar is also made by various other methods, many of which require a comparatively short time for its formation. A tumbler full of boiling milk added to fifty gallons of vinegar, and stirred into it, will clarify it, without injuring its aroma, and will also render red vinegar pale.
Good vinegar is of an agreeable, penetrating odor, and pleasant acid taste ; its color varies from pale-yellow to red, and when long kept, it becomes turbid and ropy, putrefies, becomes fetid, and loses its acidity, more especially if exposed to the air. Malt vinegar is usually of a yellowish red color ; containing from 4 to 5 per cent, of acetic acid ; wine vinegar is white or red, according to the wine it is prepared from, and is about one-sixth stronger than malt vinegar. White wine vinegar is preferred to the red, which last may be rendered pale by passing it through animal charcoal.
Vinegar may contain sulphuric acid, copper, and lead, which are its most dangerous impurities. The want of action of acetate of lead proves it free from the first ; the second may be detected by the addition of ammonia in excess, which renders the acid blue, if copper be present ; and iodide of potassium will detect lead by throwing down the yellow iodide of lead.
Properties and Uses. — Refrigerant, diuretic, astringent, and tonic. Useful in febrile and inflammatory complaints, especially when the tongue is coated dark or brown ; also in typhus and scurvy, as an antiseptic. In urinary affections, attended with a white sediment, consisting mainly of phosphate of lime, and ammoniaco-magnesian phosphate, it has been recommended. In dysentery and scarlatina, vinegar saturated with common house salt, has been very beneficial. A large tablespoonful of the mixture must be added to four of hot water, of which a tablespoonful is to be taken, as hot as may be, every two or three minutes, till the whole is consumed. A similar preparation was found very effectual in the treatment of Asiatic cholera, in Cincinnati, during 1849-50, and is also asserted to have proved a useful local application in external inflammations, sprains, bruises, swellings, etc. The vapor of vinegar inhaled into the lungs, is useful in diseases of these organs, dryness and irritation of the pulmonary tubes during measles and other exanthematous and febrile diseases, also in sore-throat; and diffused through the rooms of the sick, it is both agreeable and wholesome to the patient and attendants.
Vinegar has been used as a gargle, or its vapor inhaled, in putrid sore throat, ulceration of the fauces, hoarseness, etc. ; it has also been applied locally in some cases of ophthalmia, in epistaxis, several cutaneous diseases, and, diluted with water, has been used as an injection into the rectum in hemorrhoidal affections, and into the uterus in cases of uterine hemorrhage. It forms a valuable adjuvant to cooling lotions. The dose internally is from one to four fluidrachms ; as an injection, one or two fluidounces diluted with twice or thrice its bulk of water.
Distilled Vinegar is used for the same purposes as above, and is the solvent to be employed in making the various medicated vinegars of opium, squill, colchicum, etc. Care must be taken, when using vinegar medicinally, not to obtain the spurious and adulterated articles, containing sulphuric acid, muriatic acid, nitric acid, copper, lead, etc. One part of acetic acid to five of distilled water, forms a very good vinegar, for culinary and medicinal purposes.
Off. Prep. — Acetum Emeticum; Acetum Lobeliae; Acetum Sanguinariae ; Acetum Scillae ; Tinctura Opii Acetata ; Tinctura Sanguinariae Acetata ; Lotio Refrigerans ; Lotio Lobeliae Compositum.