Isinglass in Beer & Wine: Is Your Drink Vegan?

You check food labels carefully, but the beer or wine in your hand has no ingredient list at all. That is a problem, because some drinks are clarified with isinglass, a substance made from fish. It is removed before bottling, so it never appears on a label, and that is exactly why it catches people off guard.

Key Takeaways

• Isinglass is a gelatin obtained from fish swim bladders, used to clarify some beer and wine.
• It is not vegetarian or vegan, but it is removed before bottling, so it never appears on the label.
• Guinness famously used isinglass for decades before reformulating to be vegan.
• To be sure, look for a “vegan” label or check a vegan beer and wine directory.

TL;DR: Some beer and wine is filtered with isinglass, a gelatin made from fish swim bladders. It is removed before bottling, so it is invisible on the label, and that is why a drink can be non-vegan without saying so.

What isinglass is

Isinglass is a form of collagen obtained from the dried swim bladders of fish, historically sturgeon. In brewing and winemaking it acts as a fining agent: it is added to the liquid, binds to yeast and haze particles, and drags them to the bottom so the finished drink is clear. A brewing trade publication describes it plainly as a fish-derived fining that is not vegan-friendly (Craft Brewing Business, retrieved 2026-08-25).

The key detail is that the isinglass does the clarifying and is then filtered back out. So the glass of beer is clear, but the process used fish.

The Guinness example

This became a mainstream story because of Guinness. For decades the stout was fined with isinglass, which meant the world’s most famous beer was technically not vegetarian or vegan. It was widely reported at the time, and Guinness eventually moved to a vegan-friendly process (HuffPost, retrieved 2026-08-25). The episode is a useful reminder that even a drink with no obvious animal connection can fail a strict diet test.

Which drinks use it

• Cask ales and some traditional beers, especially in the UK and Ireland, have historically used isinglass.
• Some wines use isinglass, alongside egg white, casein (milk), gelatin or clay.

Modern breweries increasingly skip animal finings entirely, using centrifugation, cold filtration, bentonite (a clay) or plant-based finings instead. That shift is why many beers are now vegan by default even without saying so.

How to find vegan beer and wine

1. Look for a “vegan” or “suitable for vegans” statement on the bottle or the brewer’s site.
2. Check a vegan beer and wine directory such as Barnivore, which tracks brands and batches.
3. For wine, remember that egg white, casein and gelatin are also used, so “vegan wine” needs the same check.
4. When in doubt, contact the brewery or winery and ask about their fining agents.

The bottom line

A drink can look clean and still be fined with fish. Because isinglass is removed before bottling, the label will not help you, so rely on vegan certification or a directory like Barnivore.

Check before you eat. The Verify Veg app scans a barcode or reads an ingredient list from a photo and flags ingredients against your diet (vegan, vegetarian, halal, kosher, Jain and more). Download on the App Store - Android is coming soon.

Written by Samir Narain, founder of Verify Veg. Verify Veg helps people check packaged food against their diet by scanning barcodes and reading ingredient lists from photos.

Note: Verify Veg provides ingredient-based compatibility checks, not certification. Ingredient sources can vary by manufacturer, so always confirm with the brand or vendor.