Last month our brilliant gluten doctor, Dr. Vikki, wrote about the correlations between gluten and casein sensitivities. And since many of our gluten-free readers are also casein free–like me–I thought I’d share some information about one of casein’s sneakiest sources: wine.

Here’s a bit about how casein, or milk protein, can make it into your wine glass:

• Why is wine fined? Fining the wine eliminates any appearance of cloudiness by removing sediment. Fining agents, such as casein, gelatin, albumen and isinglass, are stirred into barrels of wine, where they act as magnets by picking up sediment in the wine and depositing it at the bottom of the wine barrel. Once the wine has been clarified, racking of the wine is done to separate the wine from the sediment residue.

• What ingredients are used in the fining? Casein, or milk protein. Gelatin, which is an animal protein derived from the skin and connective tissue of cows and pigs. Albumen, or egg whites. Isinglass is otherwise known as fish bladders, from sturgeon fish. Animal blood, outlawed in the US and France, this is sometimes used in Mediterranean countries. And for the more conscious vitiners, bentonite, diatomaceous earth, and carbon can be used.

• How to avoid casein and other fining agents? First of all, don’t discriminate. Cloudiness of the wine is not a reflection of quality, but rather of lack of fining. Vegan friendly vinyards allow their wines to settle naturally instead of fining with animal products. Keep in mind, organic does not mean “vegan or vegetarian friendly.” Many “organic” vinyards do fine their wines with animal proteins. If a wine is labeled vegetarian, it should not contain casein, vegan will contain no animal products. So look for these labels.

• Where to find vegetarian friendly and vegan wines? Look for the labels at your grocer, or try doing a search on Barnivore.com. And the good news is that casein free wine is not always more expensive. According to Barnivore: Charles Shaw (a.k.a. Two Buck Chuck) is not fined with casein or eggs, Bolla wines are vegan using no animal products and even Yellow Tail’s red wines are vegan. But going to the grocery without a proper list of vegan wines would simple make matters complicated, so I’ve used the resources on Barnivore to create a list of vegan friendly wines that’s perfect for taking to the wine store or a restaurant.

Cheers!