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.
This is obtained by the dry distillation of benzoin, or artificially from urine and tar products; yellowish-white, feathery, flexible, crystalline plates and needles, having an agreeable aromatic odor and a warm acidulous taste. Exposed to light it becomes darker in color, and separates a few oily drops of a brown color. It dissolves in two and one-half parts of 90 per cent. alcohol and in ten parts of glycerine. 1000 parts of distilled water at ordinary temperature, according to Bour-goin, will dissolve 2.45 parts of benzoic acid. An alcoholic solution, one ounce benzoic acid in five ounces of alcohol, is employed as a preservative. On page 757 we have recommended it for preserving citric acid solutions, the lowest effective proportion necessary having been found to be thirty-two grains of acid crystals (one part to 2000), or about three drachms per gallon of the solution. It is considered a harmless preservative, although not as powerful as salicylic acid, but can displace the latter in all cases.