Here's a new twist on an old drink: gluten-free hard liquor. Vodkas marketed as “gluten-free” hit the market last year, after a 2012 interim ruling by the Alcohol and Tobacco Tax and Trade Bureau (TTB) opened the door to such labels.

The labeling allows liquor companies to join a burgeoning industry of gluten-free products. The gluten protein, which is found in wheat, barley and rye, causes severe gastrointestinal symptoms in the roughly three million Americans suffering from celiac disease. Gluten-free diets have also become popular with other consumers.

Vodka and other pure spirits have long been white-listed for sufferers of celiac disease, even in the absence of labels. The Academy of Nutrition and Dietetics has advised that distilled spirits are gluten-free unless a flavoring or other additive has been added to the liquor. During distillation, heat vaporizes the alcohol to remove it from the mixture, leaving proteins behind. “Distilled spirits, because of the distillation process, should contain no detectable gluten residues,” says Steve Taylor, co-director of the University of Nebraska–Lincoln's Food Allergy Research and Resource Program.

Nevertheless, the makers of Blue Ice Vodka say that celiac sufferers frequently request gluten information for their products. The brand's potato vodka received gluten-free labeling in May 2013. “With the celiac and gluten-free products becoming more accessible, why not go through the process of proving we were gluten-free to ttb?” asks Thomas Gibson, chief operating officer for 21st Century Spirits, Blue Ice's parent company.

Vodka won't be the last product to don the “gluten-free” badge. Food-labeling guidelines released by the fda last year allow even foods that never had gluten, such as vegetables, fruits, eggs and bottled water, to be labeled as gluten-free.