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 also an English manufacture, and offered as an improved agent for acidulating carbonated beverages. The citro-chloric acid is, according to John 0. Thresh, D. Sc, a solution of three parts of citric acid to one of hydrochloric, and lemonade made therewith contains in ten fluid ounces two to two and one-half grains citric acid and one-half to three-fourths grains hydrochloric acid, three-quarters of a grain being the maximum; where hard waters are used the free hydrochloric acid may be reduced to nil.
The manufacturers give the following proportions to be used: to one gallon (Imp. gallon equals ten pounds) of syrup add two ounces of citro-chloric acid, and use one and one-half fluid ounces of the syrup to the full-sized (10-oz.) bottle. When a thinner syrup is preferred, add one and one-half ounces of citrochloric acid to the gallon, and use two ounces of syrup to the bottle. Measure in glass or earthenware vessel, and preserve in jars or casks with good wooden taps. It is important for manufacturers to insist upon all pipes leading from the syrup tank to the bottling machines being thoroughly drained immediately after use, as the metal is affected by the acid. While we accept the preparation of citro-chloric acid to be a cheaper acidifying agent adapted for many purposes, and believe it to be harmless provided the ratio of hydrochloric acid is never raised, we still should insist on using for all high-class beverages nothing but pure citric acid and carefully purified water.
Various other acids under mystifying names, as substitutes for citric and tartaric acids, are from time to time offered to the trade, which are nothing but mineral acids or mixtures of fruit and mineral acids, similar to the preceding.