🍷 Isinglass

Isinglass, also called fish glue, is a fining agent for wine. The OIV International Oenological Codex says it is made from the swim bladder, gills and ears of certain fish, notably sturgeon. It comes as colourless or slightly yellowish transparent sheets, mostly ribbons resembling dry parchment, or in vermiculated or powder form. It may also be supplied as a ready-to-use colloidal solution stabilised with SO2, which should be stored cool in a closed container. It is used to clarify white and rosé wines.

In the OIV International Code of Oenological Practices, isinglass is listed among the processing aids of fining (II.3.2.1) and among the admitted coagulating agents. Fining clarifies wine by adding substances that precipitate suspended particles, either by promoting sedimentation or by coagulating around the particles so that they settle with the sediment. The OIV gives these aims: to complete spontaneous clarification when it is unsatisfactory, to soften red wines by removing some tannins and polyphenols, and to clarify wines with haze or stirred-up lees. Substances used must comply with the International Oenological Codex.