Fining Agents, Seafood Allergies, and Vegetarian Concerns
Many wines, beers, vermouth, bitter liqueurs, juices, and other beverages are fined, meaning they are clarified to remove color, astringency, and/or haziness. Fining agents may include fish bladder (isinglass), chitosan (derived from shrimp shells), gelatin, egg white, milk, carbon, and clay.
The animal-derived products used in fining render many beverages unsuitable for vegetarians or vegans (even though these ingredients are filtered out of the final products).
In a molecular mixology bar setting, some bartenders are clarifying juices using a centrifuge, often using chitosan (according to instructions in Dave Arnold’s book Liquid Intelligence [link]). We are not aware of anyone having a shellfish allergy to chitosan-clarified juices. (Note that mushroom-derived chitosan is now also available.)
Allergen Studies of Fining Agents in Wine:
A basic literature search on the topic of allergens in wine fining agents, the results indicate that though some allergens from some fining agents are present in the final wines, the chances of allergic reactions to fined wines are low. (Note that these studies are only on wine, not beer or clarified cocktails.)
In "Risk of allergic reactions to wine, in milk, egg and fish-allergic patients" [link] the authors found that "Casein, isinglass or egg, remaining in traces in wine after fining, present a very low risk for the respective food allergic consumers. Physician and patient awareness campaigns may be more suitable than generalized labeling to address this issue, as the latter may have negative impact on both non-allergic and allergic consumers."
In "Potential food allergens in wine: Double-blind, placebo-controlled trial and basophil activation analysis" the authors found that [link] "Wines fined with egg white, isinglass, or non–grape-derived tannins present an extremely low risk of anaphylaxis to fish-, egg-, or peanut-allergic consumers. Although consumption of milk protein-fined wine did not induce anaphylaxis, there were insufficient subjects to determine statistically whether wines fined with milk proteins present a risk to the very rare milk-allergic consumers. In summary, the observed lack of anaphylaxis and basophil activation induced by wines made using the legislation-targeted food proteins according to good manufacturing practice suggests negligible residual food allergens in these wines."
In "Ascertaining risk of an allergic reaction from consuming wine in Australia," the author concluded [link to pdf], "Therefore, there is low if not negligible risk of an allergic reaction in an adult food allergic population to Australian wine fined with egg, fish or milk and products derived thereof, and/or to which nut-derived non-grape tannins were added."
One study ("Allergenic Proteins in Enology: A Review on Technological Applications and Safety Aspects" [link]) did find allergenic proteins still present in fined wines. "All studies measuring the residues of allergenic additives/fining agents showed that most wines at bottling were free from allergenic proteins, but in some cases relatively high quantities of them can be still present (egg white proteins more frequently than milk proteins)"
In Allergenic Proteins in Foods and Beverages [link], The authors state:
There is no indication of the existence of detect-able casein residues in the final wines able to cause allergic reactions. It is known that casein is insoluble at the wine pH. Consequently, casein is considered to be totally coagulated and sedimented. Kirschner et al. demonstrated that wines treated with fining agents containing proteins from egg, milk or fish in commercial concentrations were tolerated by consumers allergic to these proteins. Rolland et al. investigated if winestreated with fining agents containing proteins from egg,milk or fish could incite allergic reactions (anaphylaxis)in consumers with confirmed immunoglobulin E–mediated food allergy. After performing a double-blind, placebo-controlled trial, these authors concluded that no allergic reaction was induced by the consumption of wine produced with the proteins mentioned previously, according to good manufacturing practice, which suggests that the traces of fining agents remaining in the wine after treatments are insignificant. Vassilopoulou et al. also concluded that even if traces of residues of casein, isin-glass or egg proteins are found in the treated wine, the risks for allergic consumers are very low. It is known that if the wine is manufactured according to good oenological practices, the amount of processing aids that remain in the finished wine is negligible.
Shellfish Allergies and Chitosan in Wine:
According to this post [link] on the website Creative Connoisseur, Tim Vandergrift, Technical Services Manager of Winexpert makes the case that chitosan used in winemaking cannot cause an allergic reaction due to its processing. We cannot verify its accuracy in all chitosan-derived products, but it is encouraging:
Chitosan is derived from the shells of lobsters and shrimp, but the way it is processed ensures that any proteins or partial protein chains are destroyed and eliminated....After the first boil the sucrose polymers are harvested, purified, and then boiled again, to ensure that no possible level of protein can survive.
"Fining Agents" The Australian Wine Research Institute [link]
Barnivore.com Information about vegetarian and vegan beverages [link]