Believe it or not, egg whites play an important role in the wine making process, particularly when it comes to fine red wine production.
The albumen – from the Latin alba for white – found in egg whites are colloidal in nature and have a positively charged surface that attracts negatively charged tannins. Egg whites tend to remove fewer phenols and less fruit character than other fining agents, such as gelatin. Egg whites also tend to favor harsh and bitter tannins, leaving the softer ones behind in the wine.
Fining is done to improve color and clarity, as well as to enhance flavor and stability. Five egg whites can do the job for a 225 l/59 gal barrel of young, red wine. Fining can save money for the producer (and for you) because it saves time – most fine wines held under good conditions for a few months would achieve the same clarity as fining.
Other fining substances have been derived from milk, fish bladders, and American bentonite clay deposits. If any of this grosses you out, research conducted at UC Davis found that insignificant traces, at most, of any fining agent remains in the final wine. Nevertheless, many producers are moving away from animal-based products for the sake of vegetarians and vegans.