This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Acid Acetic of the spec. grav. of 1.048 U. S., 1.044 Br., 1.040 P. G., containing hydrogen acetate 36° U. S., 32° Br., and 29° G, Diluted Acetic Acid (Vinegar).- Acetic acid, nine fluid ounces; distilled water, forty-six fluid ounces (United States); acetic acid, one pint; and distilled water, seven pints, British. Both are sometimes employed as an acidulous agent to carbonated beverages.
On diluting with alcohol or distilled water, the acid should remain transparent, and on evaporating it in a water bath no residue should be left, which would indicate saline impurities. Sulphuric acid is detected in the diluted acid by adding some chloride of barium, when the insoluble sulphate of barium will occur as a precipitate. Hydrochloric acid is in the same way detected by nitrate of silver, chloride of silver precipitating. Nitric acid is detected by dissolving a little brucine in the diluted acetic acid, and an orange-red color appearing. The presence of sulphurous acid may be ascertained by adding some solution of potassium permanganate and disappearance of the color, Its Employment for Acidifying Carbonated Beverages. - The British bottling trade is doubtless better acquainted with the acidulant properties of acetic acid, as used in connection with carbonated drinks, than its American cousin. It may be safely said that its use in the United States is not only unknown, but condemned, and most properly. Acetic acid is the acetous principle of vinegar, to which the palate is very sensitive, and the slightest traces of which are enough to give the beverage a most unpleasant taste of that liquid. Whatever else acetic acid may be adapted for, such as in sauces, relishes and pickling, it is certainly not fit to enter into the composition of any article intended for a beverage. The harsh acerbity of a sauce bears no resemblance to the pleasant acidity of a carbonated drink; and whether the employment of acetic acid among bottlers is favorably regarded or not, we unhesitatingly advise to abstain from its use, and employ citric or tartaric acid.