Is Isinglass Vegan?
No — from fish bladders.
Contains or is derived from animal products.
Isinglass profile
Isinglass
- Also known as
- Fish bladder finings, Icthyocolle, Swim bladder collagen
- Typical source
- Dried swim bladders of sturgeon and other fish (often Russian sturgeon or tropical species)
- Source type
- Animal
- Common function
- Fining agent to clarify alcoholic drinks by removing yeast and proteins
- Vegan status
- Processing aid, not an ingredient; usually omitted from final labels but may leave trace residues
Detailed answer
No. Isinglass is not vegan. It is a fining agent made from dried fish swim bladders, used to clarify beer and wine. It rarely appears on finished labels.
What is isinglass?
Isinglass is a form of collagen extracted from fish swim bladders, the gas-filled organ that helps fish control buoyancy. When dissolved in beer or wine, it binds to suspended yeast and protein particles and settles to the bottom, leaving a clear drink. The finings are filtered out before bottling, which is why isinglass often does not appear on the ingredient list even when used.
How isinglass is used in brewing and winemaking
- Isinglass is rinsed and dissolved in water or beer to form a fining solution.
- The solution is added to cask beer or wine while still in the vessel.
- Isinglass forms a gel that attracts yeast haze and tannins, pulling them down as sediment.
- The clarified liquid is racked or filtered off the sediment before packaging.
- Final labels list grapes, barley, hops, or yeast, not isinglass, even though it was used in production.
Drinks most likely to involve isinglass
- Cask-conditioned real ale (traditional UK pubs)
- Some bottled and keg beers, depending on brewery
- Certain white and sparkling wines
- Older or traditional winery methods
- Home-brew recipes calling for finings
Isinglass vs other fining agents
| Fining agent | Source | Vegan? |
|---|---|---|
| Isinglass | Fish swim bladder | No |
| Gelatin | Animal collagen | No |
| Casein / milk protein | Dairy | No |
| Bentonite clay | Mineral clay | Yes |
| PVPP / plant finings | Synthetic or plant | Yes |
Why isinglass is a label problem for vegans
Fining agents are classified as processing aids in many countries, not ingredients. A beer filtered with isinglass can still legally list only water, malt, hops, and yeast. Vegans who avoid all animal use in production need brewery or winery confirmation, vegan certification, or databases like Barnivore.
Ingredient lists won't show isinglass. Read our guide to vegan alcohol
Frequently asked questions
- Is Guinness vegan?
- Guinness Draught in cans, bottles, and kegs has been vegan since 2018, when isinglass was removed from filtration. Other Guinness variants may differ; check each product.
- Is isinglass listed on beer labels?
- Usually not. It is a processing aid filtered out before sale. The finished label often omits it entirely.
- Which fish are used for isinglass?
- Historically Russian sturgeon bladders were prized. Today tropical fish such as tilapia or catfish bladders are also used in commercial finings.
- Are cask ales vegan?
- Often not. Traditional cask ale frequently uses isinglass as a fining. Ask the pub or check the brewery's vegan list.
- How do I find vegan beer and wine?
- Look for vegan labels, check Barnivore, or choose unfined/unfiltered products that skip animal finings.
- Is wine always fined with isinglass?
- No. Many wineries now use bentonite clay or skip fining. But isinglass remains common enough that vegan drinkers verify by brand.
Evidence
Last verified August 2026
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Checked by Is This Vegan? · August 2026