Why are there fish bladders in beer?

This is a common misconception that likely stems from the use of isinglass, a substance derived from the swim bladders of fish, in some beer fining processes.

Fining is a process used to clarify beer, removing any remaining haze or cloudiness. Isinglass is a natural protein that attracts and binds to particles in the beer, causing them to settle out.

However, isinglass is not the only fining agent used. Many other substances like gelatin, bentonite clay, and PVPP (polyvinylpolypyrrolidone) are also used.

It's important to note that:

* The use of isinglass is decreasing as more brewers opt for vegan fining agents.

* The isinglass itself is removed during the filtration process, so there is no trace of it in the final beer.

* Most beers today do not use isinglass at all.

So, while some beer may have been fined with isinglass at some point, it's safe to say there are no fish bladders in your beer.