Are egg whites really used in winemaking?

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Dear Dr. Vinny,
On a trip to the West Coast recently, I found an interesting wine shop that specialized in small-run wines. A gentleman working there told me about a winemaking technique that uses egg whites to mellow out tannins. I found it hard to believe, but he said that it was "old school" German winemaking. I bought a bottle, but I'm wondering if there's any truth to this egg-white thing.
—Lionel, Glenside, Pa.
Dear Lionel,
You'd be surprised how common egg whites are in the production of wine. Egg whites (as well as powdered clay, gelatin and even fish bladders) can be used in the "fining," or clarification and stabilization, of wines. These fining agents are added to a wine to coagulate with sediment particles and settle to the bottom, where they can be easily removed. Egg whites are popular for their high content of albumin (a type of protein), which make them a good tool for fining wine because they gently absorb harsh and bitter tannins, leaving behind softer tannins.
We're talking regular, store-bought eggs, by the way. Two or three egg whites are all you need for a 55-gallon barrel of wine. The leftover yolks hopefully go into a soufflé.
This is definitely "old school" winemaking, although there's also a camp of "purist" winemakers who don't believe in fining or filtering wines at all, because they feel that it strips a wine of its character. Anyway, fining has been around for centuries, and it's not specific to German winemaking.
—Dr. Vinny