The Real Reason Some Wine Isn't Vegan
In the wide world of wine, there are far more alternative categories than natural and contact wines. Those who are new to veganism, vegetarianism, or even just trying to cut down on meat or animal product consumption to some degree, though, might be in for a rude awakening. Wine is made of grapes, yes, but the process itself is not exactly animal-friendly in some cases.
To put your immediate fears to rest, vegans and vegetarians have not been drinking any sneaky animal products in wine — the issue is that animal products that are often used in the process of making wine. Most wine is processed so that the color is bright and the drink is transparent — unlike natural wine, which is cloudy with natural sediment. However, to make the wine transparent, the liquid must be put through "fining" which removes those sediments more quickly than if the wine sat for a long period, settled, and underwent this process on its own (via The Kitchn).
"Fining" calls for some animal products or types of proteins to be dropped into the wine. The fine particles and sediments that are in the wine are naturally attracted to those proteins causing it to coagulate or form a large particle that is easier to remove. These products are usually egg whites, casein (milk protein), and gelatin (made from animal hide and bones) among others (via Wine Enthusiast).
Vegan- and vegetarian-friendly alternatives
Some other animal products that are used for "fining" are far from appetizing. They include isinglass, which are the swim bladders of fish like sturgeon, and chitosan, which is a carbohydrate made from the crushed up shells of crustaceans. Depending on the color and types of wine, different agents are used because they have different effects on the appearance of the final wine product.
All hope is not lost for vegans and vegetarians, though. While some of the widely-used agents are vegetarian-friendly, like egg whites and casein, there are plenty of other alternatives. Vegans just have to be as diligent as ever to check labels or do research ahead of shopping for brands that use plant-based agents.
According to PETA, some wineries use products like limestone, kaolin clay, plant casein, silica gel, and other alternatives to refine their wine. The Kitchn also suggests wines that used activated charcoal to remove the sediments. PETA also lists a few vegan wines that the organization suggests like Cooper's Hawk Vineyards, Frey Winery, Palmina Wines, Smithfield Wine, and Thumbprint Cellars among others.