Is Isinglass Vegan?

What is Isinglass?

A form of collagen used primarily as a fining agent (clarifier) to filter out particulate matter in the production of some wines and beers.

How Isinglass is made

Fish swim bladders (most often from sturgeon or cod) are dried and processed into thin sheets. Brewers and winemakers add the sheets to fermenting beer or wine, where the collagen binds to suspended yeast and tannin particles, dragging them to the bottom of the tank. The clarified liquid is then drawn off — the isinglass settles out with the lees and isn't in the finished product, but it touches every drop on the way through. Modern alternatives like bentonite clay, silica gel, and PVPP achieve the same clarity without animal input.

History and context

Isinglass has been used since the 18th century, originally as a clarifier for wine and Russian caviar before it became standard in cask ale. Guinness famously dropped isinglass in 2018 after centuries of use — a single high-profile reformulation that prompted dozens of cask breweries to follow.

Common misconceptions

"Vegan beer" isn't a regulated label in most countries. Many craft beers are accidentally vegan because they don't use animal fining at all — but the only reliable way to verify is the Barnivore database or the brewery's public statement.

Where Isinglass usually appears

You can frequently find this ingredient hiding in:

• Certain traditional beers
• Some wines
• Cask ales

Vegan alternatives to Isinglass

If you're avoiding isinglass, look for these plant-based alternatives instead:

• Bentonite clay
• Irish moss
• Silica gel
• Polyvinylpolypyrrolidone (PVPP)