Using the Whole Fish: Meat, Leather and Isinglass

A sturgeon can provide much more than caviar: its meat is sold fresh, frozen or smoked, its skin can become leather, and its swim bladder can supply isinglass. Isinglass is collagen from fish used to clarify some beers and wines. Drinks made with it do not meet the Vegetarian Society's vegan or vegetarian certification criteria, even when the fining material is largely removed.

Sturgeon meat has its own food traditions

After a conventional caviar harvest, the carcass can enter a separate food-processing chain rather than being discarded. FAO documents fresh, frozen and smoked sturgeon meat, as well as preparations including pan-frying, baking and broiling. A farm's actual outlets depend on its processing arrangements and customers, so these documented uses should not be read as a promise that every caviar producer uses every part.

Russian cooking also offers a distinct example of using more than the fillet: viziga, also written vyaziga, is prepared from the sturgeon's notochord, the supporting cord along its body.

These are not simply new ways of dealing with caviar waste. NOAA's historical account describes smoked and pickled sturgeon meat in North America, where preservation helped it travel. Russian cooking also offers a distinct example of using more than the fillet: viziga, also written vyaziga, is prepared from the sturgeon's notochord, the supporting cord along its body.

In a documented 2017 demonstration, chef Gleb Astafyev used viziga with sterlet, rice, mushrooms and eggs in kulebyaka, a filled pie. For the harvest itself, see harvesting caviar; the separate question of male fish belongs in male sturgeon on farms.

From skin to leather

Fish leather is skin that has been cleaned and tanned, not merely dried. Tanning stabilises the material for use as leather; preparation also removes adhering flesh and unwanted fat. Research published by the Society of Leather Technologists and Chemists describes sturgeon-skin processing that combines fleshing, repeated degreasing and bleaching while trying to preserve its distinctive surface structure.

That study identifies bags as a possible application. India's Council of Scientific and Industrial Research lists wallets, belts, watch straps and shoes as possible applications for fish leather generally. A finished item's species and origin need their own documentation; a fish-like texture is not an identification.

The parts and their documented uses

Isinglass, and why some beers and wines are not vegan

Isinglass is a collagen preparation obtained from fish swim bladders, organs that help regulate buoyancy. Its association with sturgeon is historical and genuine: NOAA records sturgeon isinglass used as an adhesive and paint binder. It should not, however, be assumed that a modern brewery's finings came from a caviar farm.

The Brewers of Europe's technical guidance describes brewing isinglass from tropical and subtropical fish. The Oxford Companion to Beer names Nile perch among modern sources and contrasts these with traditional sturgeon supplies. According to the Brewers of Europe, brewing isinglass comes from specific tropical and subtropical fish.

What fining does

Fining means adding a material that helps unwanted suspended matter gather together and separate from the drink. In beer, positively charged collagen binds to negatively charged yeast cells, forming larger clumps that settle more readily. In cask-conditioned beer, that sediment remains in the cask while clear beer is drawn off above it.

In wine, isinglass helps clarification and can remove some phenolic compounds associated with harshness. The Australian Wine Research Institute describes its use particularly in white wines, followed by separation from the sediment. It also warns that excessive additions can leave residual protein, so 'used during processing' is not equivalent to 'guaranteed absent afterwards'.

Why removal does not make it vegan

The Vegetarian Society's vegetarian and vegan trademark criteria exclude isinglass. Its vegan criteria also exclude other processing aids derived from animals. The objection is the deliberate use of a fish product to make the drink, not just how much can be measured in the glass. Removing the sediment therefore does not turn an isinglass-fined drink into a qualifying vegan product.

To check a drink, look for a recognised vegan certification or ask its producer whether any animal-derived fining or processing aids were used. Identify the exact beer, or the wine and vintage, rather than asking about a whole brand. A useful question is: 'Was this drink made using isinglass, gelatine, egg or milk-derived finings?'

Unfined drinks and those made with non-animal finings offer other routes, but clarity alone tells you nothing about suitability. For serving rather than production, see beer, sherry and cocktail pairings.

Why the label may not mention fish

Allergen disclosure and vegan suitability answer different questions. The following rules concern isinglass used to clarify beer or wine, not a general exemption for fish ingredients. The legal position was checked in November 2026.

The US row is not a rule for every alcoholic drink. FDA-regulated products fall under federal food-allergen law: an allergenic processing aid does not acquire an automatic exemption merely because it is a processing aid. The TTB position should therefore not be applied to an FDA-regulated product.

The UK Food Standards Agency says 'vegan' is not defined in food law, although claims must not mislead. Private certification is a separate standard, not an allergen guarantee. If you have a fish allergy, ask your clinician for individual advice rather than using vegan status as a safety test.

CITES follows the fish beyond its roe

CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, covers listed animals and their recognisable parts and derivatives, not just live fish or caviar. Its listings include both sturgeons and paddlefish. Sturgeon meat, skins, leather and sturgeon-derived isinglass can therefore fall within its controls. Farming is not, by itself, a permit exemption, and non-sturgeon isinglass must be assessed by its own source species.

For commercial trade across the EU's external border, Regulation 338/97 sets import and export requirements, with implementing procedures in Regulation 865/2006. Great Britain operates its amended, assimilated wildlife-trade regime; Northern Ireland remains under the EU framework. US wildlife authorities may require CITES documents for international trade in sturgeon products, depending on the species, origin, destination and applicable exemptions. Additional species protections may also apply.

These are border controls, not a claim that each domestic sale needs an import permit. Before shipping meat or leather, establish the species, documented origin and destination, then consult the relevant wildlife authority. Resolution Conf. 12.7 (Rev. CoP17) provides caviar labelling rules, not universal leather labels; see CITES and caviar for the wider framework.

What whole-fish use can tell you

Exmoor Caviar presents using the whole fish as part of its sustainability approach and states that it sells fresh, hot-smoked and cold-smoked sturgeon. That is a producer's account of its practices, not an independent environmental assessment. Useful scrutiny asks which parts actually become products and what evidence supports the claimed reduction in waste.

Using more of an animal is a meaningful resource-use question, but it does not answer every question about farming. Keep claims about by-products separate from evidence about the farm's wider impacts, explored in the environmental footprint of caviar farms.