Isinglass is derived from the swim bladders of certain tropical and subtropical fish. When macerated and dissolved for several weeks in dilute food-grade acids, they form a turbid, colorless, viscous solution largely made up of the protein collagen. This material is known to brewers as isinglass finings.

Where does isinglass come from?

Isinglass, also known as fish glue, comes from the membrane of the “sounds” (air/swim bladders) of certain kinds of fish. It has been used for centuries as a fining, or clarifying agent, in alcoholic beverages. Finings remove particles like the yeast used in fermentation.

What animal does isinglass come from?

Isinglass (/ˈaɪzɪŋɡlæs, -ɡlɑːs/) is a substance obtained from the dried swim bladders of fish. It is a form of collagen used mainly for the clarification or fining of some beer and wine. It can also be cooked into a paste for specialised gluing purposes.