Isinglass is a substance obtained from the swimbladders of fish (especially Beluga sturgeon). It is a form of collagen used mainly for the clarification of wine and beer. Use in foods and drinks Prior to the inexpensive production of gelatin and other competitive products, isinglass was used in confectionery and desserts such as fruit jelly and blancmange. Isinglass was originally made exclusively from sturgeon, until the 1795 invention by William Murdoch of a cheap substitute using cod. This wa… (More on Isinglass)