Not Vegan
Derived from the dried swim bladders of fish (particularly sturgeon, cod, and tropical fish). Used as a clarifying agent.
Ingredient Data
Not Vegan
Derived from the dried swim bladders of fish (particularly sturgeon, cod, and tropical fish). Used as a clarifying agent.
Beer, wine, and cider. Used during the brewing/winemaking process to remove yeast particles and sediment.
Irish moss (carrageenan), bentonite clay, activated charcoal, or unfiltered/naturally clarified beer.
Not listed on ingredient labels in most countries because it is a 'processing aid' not a final ingredient. Many mainstream beers (e.g., Guinness until 2016) used isinglass. Use Barnivore.com to check whether specific beers and wines are vegan.
In depth
Isinglass is a nearly pure form of collagen obtained from the swim bladders of fish. Historically the primary source was sturgeon, particularly from Russia, which is why older texts refer to it as Russian isinglass. As sturgeon became scarce and expensive, producers shifted to other species, and modern isinglass is commonly made from other fish, including cod and various tropical species. The bladders are removed, cleaned, and dried, then treated with a dilute food-grade acid that dissolves the collagen into a viscous liquid or paste.
In a brewery or winery, this collagen preparation is added after fermentation as a fining agent. The collagen molecules carry a positive electrical charge, while yeast cells and haze-forming particles carry a negative charge. The two attract, forming larger clumps that sink to the bottom of the tank far faster than they would settle on their own. The clarified liquid is then drawn off the sediment, meaning most of the isinglass is left behind rather than consumed, though trace residues can remain in the finished product.
Isinglass is one of the clearest examples of why ingredient labels alone cannot confirm whether a drink is vegan. In most jurisdictions, substances used to process a food or beverage and then substantially removed are classified as processing aids rather than ingredients, and processing aids are generally exempt from ingredient labeling. Because isinglass is added to clarify a beer, wine, or cider and then settles out with the sediment, producers are typically not required to declare it.
The problem is compounded by the fact that alcoholic beverages in many countries, including the United States, are largely exempt from standard ingredient-labeling rules in the first place. A beer fined with isinglass and a beer clarified by filtration can carry identical labels. The practical workarounds are to look for an explicit vegan certification mark on the packaging, to consult the crowd-sourced database Barnivore.com, or to contact the producer directly. Many breweries and wineries now answer this question openly on their websites or FAQ pages.
Producers have a range of animal-free options for clarifying beer, wine, and cider. Bentonite, a natural clay, is the standard fining agent for removing haze-causing proteins in winemaking and works well in cider. Silica gel and activated charcoal are also widely used and vegan. In brewing, Irish moss and other carrageenan-based preparations are added during the boil to help proteins coagulate, and they are derived from seaweed. Synthetic options such as PVPP (polyvinylpolypyrrolidone) remove haze-forming polyphenols without any animal input.
Beyond fining agents, many producers skip additives entirely. Mechanical filtration and centrifugation achieve bright, clear results at industrial scale, which is why most mass-produced lagers are incidentally vegan. Cold conditioning, in which the beverage is simply held at low temperatures for an extended period, lets particles settle naturally, though it takes longer and occupies tank space. Finally, a growing segment of craft producers embraces intentionally hazy or unfiltered styles, where clarification is unnecessary. These animal-free methods are widely used in commercial production, and isinglass persists mainly in certain traditional brewing contexts.
Isinglass is most strongly associated with traditional British brewing. Cask-conditioned ales, the style served from hand pumps in UK pubs, commonly rely on isinglass finings dropped into the cask so the beer clears in the cellar before serving. Drinkers who assume beer is just water, malt, hops, and yeast are often surprised that a fish-derived product may have been used along the way.
The best-known example is Guinness, which used isinglass in its production process for much of its history before announcing a switch to a new filtration system; draught Guinness became suitable for vegans in 2016, with packaged formats following. Wine and cider are the other major categories: isinglass is favored for white wines because it clarifies without stripping color, while ciders from traditional producers may also be fined with it. Spirits, by contrast, are generally not affected, since distillation leaves fining agents behind. As always, the absence of isinglass on a label proves nothing, so certification marks or producer confirmation remain the reliable checks.
Frequently asked questions
No, isinglass is not vegan. It is a form of collagen made from the dried swim bladders of fish, so it is an animal product. It is also unsuitable for vegetarians, and beverages clarified with it are not considered vegan even though little to none remains in the final drink.
It is in some beer, but not all. Isinglass is traditional in British cask-conditioned ales and was historically used by many large breweries, while most mass-produced lagers rely on filtration instead. Because it is a processing aid, it will not appear on the label, so check Barnivore.com or the brewery's website to confirm a specific beer.
No. Guinness switched to a new filtration process, making draught Guinness suitable for vegans in 2016, with bottled and canned formats following afterward. Before that change, the stout had been clarified with isinglass for most of its history.
Because it is legally classified as a processing aid rather than an ingredient. It is added to clarify the drink and then settles out with the sediment, so most labeling rules do not require it to be declared. In addition, alcoholic beverages in many countries are exempt from full ingredient labeling altogether.
Common vegan alternatives include bentonite clay, silica gel, activated charcoal, carrageenan-based Irish moss finings, and the synthetic agent PVPP. Many producers avoid fining agents entirely by using mechanical filtration, centrifugation, or extended cold conditioning. Unfiltered and intentionally hazy styles skip clarification altogether.
Sometimes. Isinglass is one of several animal-derived fining agents used in winemaking, alongside egg whites, casein, and gelatin, and it is particularly favored for clarifying white wines. Many wineries use vegan alternatives such as bentonite instead, so look for a vegan label or check the producer's fining practices.