Are distilled spirits gluten free?

Fermented liquid boiled and recondensed. What crosses over in a still is alcohol, water and volatile aromatics; what stays behind is everything heavy, and protein is heavy. That single physical fact is the whole answer for the entire category — whisky from barley, vodka from wheat, gin from grain alcohol.

Because the starting material is openly a gluten grain and says so on the bottle. Scotch is barley. Rye whiskey is rye. Many vodkas are wheat. Somebody who has learned to read for grain names finds them in enormous letters on the front label, and the instinct to put it down is a good instinct applied to the one case where it does not hold.

FDA — packaged food

Distilled spirits are gluten-free regardless of what they were made from, and the FDA verifies this category by confirming the absence of protein rather than by tracing the source grain. A distillate cannot carry gluten protein across, so the question of what went into the mash is simply not the question.

Elsewhere

The exception is anything added after distillation. A flavoured vodka, a whisky liqueur, a spiced rum, a pre-mixed cocktail or a barrel finish involving a flavouring can introduce something the distillation never touched. The spirit is safe; the things done to it afterwards are an ordinary ingredient question.

Plain spirits are fine, and that includes the ones that sound least fine. Where to actually look: flavoured and cream liqueurs, anything with a colour that did not come from a barrel, and beer-based or malt-based pre-mixes, which are not spirits at all despite sitting in the same fridge. Worth knowing that a persistent reaction to a spirit is more likely about the mixer, the garnish or the shared bar equipment than the distillate.

• 21 CFR 101.91 — distilled products and the 20 ppm standard
• TTB policy on gluten content statements for distilled spirits