Why Some Wine Actually Isn't Vegan

Many wine drinkers may be shocked to discover that some of their favorite grape-based fermented beverages are not technically vegan or even vegetarian. While animal products won't make it onto the ingredients list, they are sometimes used as an aid in producing tasty, visually appealing wines. Some common animal-derived products that go into the winemaking process include egg whites, milk protein, gelatin, and derivatives from the swim bladders of fish and crustacean shells. Some of the same products are used in beer brewing, making some beers non-vegan as well.

By and large, these additives are effective at speeding up a process known as "fining," which describes the clarification process by which sediment and solids are separated from the wine, leaving a clear and crisp white or a robust and balanced red. Without intervention, the clarifying process can take months. But with market demands to meet and the help of modern science, fining can be sped up with the use of animal-derived processing aids. So, while you may not be able to taste any dairy in your sauvignon blanc, it's likely that milk may have played a part in its journey to your glass.

The chemical art of fining a wine

While adding "fining" agents isn't strictly necessary when making wine, and vegan wines do exist, the desire to create clear wine quickly has made the use of animal products fairly widespread in the industry. After fermentation, the wine is full of residual elements that give it a hazy appearance. Molecules like tartrates and tannins can fog up the wine and, while perfectly safe to drink, it's not very visually appealing in a glass and may make a wine less palatable. Certain additives, when used correctly, remove the excess chemical compounds that can negatively impact color, taste, and texture. 

One of the oldest fining agents still used in modern winemaking is egg whites, a common practice in the French Bordeaux region for generations. The ever-popular cabernet sauvignon, a traditional Bordeaux varietal, is high in tannins. While the right amount of tannin can be a pleasant aspect of well-balanced beverages, too much makes for a bitter, astringent wine (and is also a potential reason red wine can cause headaches). One way of removing some of these tannins is by stirring egg whites into the wine. Young tannins bind to the egg whites, which sink to the bottom of the barrel and are separated before the wine ever sees the inside of a bottle. For white wines, an oft-used fining agent is casein, a milk protein. Casein helps remove elements of oxidation, making for brighter, less bitter white wines.

Understanding non-vegan and non-vegetarian additives

While wines that are made using egg whites or milk aren't technically vegan, they can still broadly be considered vegetarian since they are made with products naturally produced by animals but do not require slaughter. Some other fining agents, not so much. Gelatin, common in many foods from marshmallows to canned meat, is made from the bones and hides of various animals. It can be useful for fining both red and white wines, removing tannins, and adding clarity. Isinglass is another additive that vegetarians may want to steer clear of, as it's a protein derived from the swim bladders of fish. Though it is not as common in winemaking as it once was, it is sometimes used to clarify white wines and improve their flavor.

The vegan distinction for food and beverages is not one regulated by a governing body like the USDA or FDA — it's a label that greatly relies on winemaker transparency and comes with a level of trust in the producer. There are, however, independent organizations that seek to vet and certify vegan wines, making it easier for consumers to find wines that align with their values or dietary choices. Awareness of winemaking procedures is not only key to appreciating the work that goes into your glass but can be an important part of the decision-making process when it comes to understanding the wine you buy.