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 fins to produce lift while swimming. The gas/tissue interface at the swim bladder produces a strong reflection of sound, which is used in sonar equipment to find fish. Cartilaginous fish, such as sharks and rays, do not have swim bladders. Some of them can control their depth only by swimming (using dynamic lift); others store fats or oils with density less than that of seawater to produce a neutral or near neutral buoyancy, which does not change with depth. The swim bladder normally consists of two gas-filled sacs located in the dorsal portion of the fish, although in a few