Isinglass, << Y zihng `glas,` >> is the purest form of animal gelatin. It is a tough, semitransparent silvery-white substance. Beverage makers use isinglass to remove unwanted particles from fruit juices and alcoholic drinks. It is also used to make certain cements and to repair parchment, a paperlike material made from animal skin.
Isinglass is made from an organ in certain fish called the swim bladder. The best-quality isinglass comes from the Russian sturgeon. Isinglass also comes from carp, catfish, cod, hake, and other fish. To prepare isinglass, manufacturers soak the bladder in cold water and take off the black outer skin. Next, they wash the remaining part and dry it. Workers dampen the bladder in warm water and remove the inner skin by rubbing and beating. Then, they pass it between rollers, which reduce it to a thin, partly transparent ribbon.
