Aerated Waters or Carbonated Bever Ages

AERATED WATERS or CARBONATED BEVER AGES. These may be divided into two classes, namely, aerated table-waters and effervescent beverages. The latter are flavoured and are known in the United States as carbonated beverages, also as "soda-water," "soda" and "pop" and include ginger-ales. Natural and synthetic flavours are used. Natural flavours are from fruits, nuts, roots, herbs, bark and leaves of plants.

Synthetic flavours are also made in the laboratory. Aerated waters are essentially non-alco holic beverages artificially satu rated at the normal temperature with carbon dioxide, the pressure varying according to the type of beverage. Artificially aerated waters had their inception in Priestley's success in 1772 in producing aerated water in imi tation of naturally aerated min eral spring water. Large-scale manufacture of aerated water was commenced by Paul at Geneva in i790 and shortly after wards by Schweppe in London. In the United States Priestley's experiments interested a Phila delphia physician, Dr. Philip Syng Physick, and he induced a chemist, Townsend Speakman, of the same city, to prepare car bonated water for his patients. Speakman added fruit juice as a flavour and the soft-drink indus try in the United States started at that time, 1807. From the original conception of the imita tion of natural carbonated water from springs the industry has broadened to include the produc tion of aerated sweetened drinks and substitutes for beverages, such as cider, which are aerated by fermentation. The technique of large-scale aerated-water manufacture and the apparatus employed have undergone very considerable improvement within the last 20 years. Small-scale production of aerated water has also been rendered much simpler than formerly, when the cumbersome seltzogene apparatus was the only means for small-scale aeration of water.

Raw

in the manufacture of aerated waters are water, carbon dioxide, sugar and certain artificial sweeteners, acidifying materials, fruit juices, artificial fruit essences, essential oils, vegetable extracts, mineral salts and foam-producing mate rials. The water employed must be unexceptionable as regards purity, both from chemical and bacteriological standpoints. To this end it is customary to filter the water through an effective filtering medium, for example, kieselguhr, unglazed porcelain, filter-paper or cloth. The water must also be free from objection able colour, odour and taste. It is sometimes necessary to rectify waters which are either too hard or too soft for the purpose in view, also in some cases manufacturers use distilled water for special purposes. Carbon dioxide is produced as a by-product in the combustion of coke in burning limestone to quick-lime, or from sulphuric acid and carbonates, or recovered as a by-product from fermentation processes. It is either made in a special gas generator in the aerated-water factory or is purchased in a highly compressed or liquefied state in steel cylinders. In either case it must be free from objectionable taste. Carbonation furnishes in the finished beverage a gaseous pressure of from 4o to 8o lb. per square inch depending upon the type of product. High-pres sure carbonation is used on ginger-ales, and is carried on at about 55° and impregnates the beverages with as high as four and one half volumes of gas. Low pressure is used on fruit drinks, at about 40° to 42° and as low as one volume of gas may be employed.