The question of whether distilled spirits like vodka, gin, tequila, and other hard liquors are safe for people who are sensitive (whether due to allergy or intolerance) to the grains they're distilled from is somewhat controversial. In fact, little research has been done on the subject. The European Food Safety Authority considers distilled alcohol "unlikely to cause a severe reaction" in those with grain allergies and the Canadian Celiac Association allows distilled alcoholic beverages for celiacs even if they're made with wheat, rye, or barley, since the distillation process should remove the reaction-causing proteins. However, the Celiac Sprue Foundation recommends no hard liquor from grains containing gluten, at least during the early phases of a gluten-free diet. Many people with wheat allergies and other grain allergies choose to avoid distilled alcohol, either out of caution or because they find that it does exacerbate their symptoms.
While tequila is always made from agave, many distilled spirits (especially vodka) can be made from a variety of grains. Whiskey is normally made from wheat, but you may be able to find corn whiskey at some retailers. Gin is difficult to get accurate information on because most manufacturers keep their flavor blends proprietary. Most, however, are made from wheat or rye with a blend of botanicals including juniper berries, citrus peels, nuts, and herbs.
Vodka can be made from numerous grains and plants, but two predominate: wheat and potatoes. Barley, rye, corn, and grape vodkas are also available. Potato vodkas and grape vodkas are generally considered "high-end" vodkas, although some wheat vodkas are considered premium as well. Here's a rundown of the base grains for common vodkas:
- Wheat: Stolichnaya (made from a blend of wheat and rye), Grey Goose, Ketel One, Snow Queen, Van Gogh (made from a blend of wheat, corn, and barley), La Chance, Vox, Polar Ice, Absolut
- Rye: Belvedere
- Barley: Finlandia, Koskenkorva
- Corn: Smirnoff
- Potato: Chopin, Teton Glacier, Monopolowa, Vikingfjord, Luksosowa
- Grape: Cîroc, Bombora