Vegetarianism and beer a yeasty flavour. Finings are used to clear the beer of yeast – there are a variety of agents used as finings, including silicon dioxide, gelatin, polyclar, and isinglass. Isinglass is the most common fining used to clear cask ale. Isinglass is produced from the swim bladders of fish, usually sturgeon, though also those in the polynemidae, sciaenidae and siluridae families; as it is an animal product, cask ale cleared with isinglass is not considered vegetarian. A brewer may also use some form of animal product in the later stages of beer processing, such as glycerol monostearate, which is used
Swim bladder delicacy. In China they are known as "fish maw", 花膠/鱼鳔, and are served in soups or stews. The vanity price of a vanishing kind of maw is behind the imminent extinction of the vaquita, the world's smallest dolphin breed. Only found in Mexico's Gulf of California, the once numerous vaquita now number less than 60 in total. Vaquita die in gillnets set to catch totoaba (the world's largest drum fish). Totoaba are being hunted to extinction for its maw, which can sell for as much $10,000 per kilogram. Swim bladders are also used in the food industry as a source