This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Clarification is the process by which any solid particles suspended in a liquid are either caused to coalesce together or to adhere to the medium used for clarifying, that they may be removed by filtration (which would previously have been impossible), so as to render the liquid clear.
One of the best agents for this purpose is albumen. When clarifying vegetable extracts, the albumen which is naturally present in most plants accomplishes this purpose easily, provided the vegetable matter is extracted in the cold, so as to get as much albumen as possible in solution.
Egg albumen may also be used. The effect of albumen may be increased by the addition of cellulose, in the form of a fine magma of filtering paper. This has the further advantage that the subsequent filtration is much facilitated.
Suspended particles of gum or pectin may be removed by cautious precipitation with tannin, of which only an exceedingly small amount is usually necessary. It combines with the gelatinous substances better with the aid of heat than in the cold. There must be no excess of tannin used.
Another method of clarifying liquids turbid from particles of gum, albumen, pectin, etc., is to add to them a definite quantity of alcohol. This causes the former substances to separate in more or less large flakes. The quantity of alcohol required varies greatly according to the nature of the liquid. It should be determined in each case by an experiment on a small scale.
Resinous or waxy substances, such as are occasionally met with in honey, etc., may be removed by the addition of bole, pulped filtering paper, and heating to oiling. In each case the clarifying process may be hastened by making the separating particles specifically heavier; that is, by incorporating some heavier substance, such as talcum, etc., which may cause the flocculi to sink more rapidly, and to form a compact sediment.
Clarifying powder for alcoholic liquids:
Egg albumen, dry.... 40 parts
Sugar of milk........ 40 parts
Starch.............. 20 parts
Reduce them to very fine powder, and mix thoroughly.
For clarifying liquors, wines, essences, etc., take for every quart of liquid 75 grains of the above mixture, shake repeatedly in the course of a few days, the mixture being kept in a warm room, then filter.
Powdered talcum renders the same service, and has the additional advantage of being entirely insoluble. However, the above mixture acts more energetically.