Conventional wisdom is that, even though alcoholic spirits such as whiskey, bourbon, and gin are brewed from grain ingredients, the process of distillation (i.e., heat used to provoke evaporation of volatile contents, followed by condensation) reduces gluten residues to low levels. Limited testing has measured 20 parts per million gluten or less in these spirits, below the FDA cutoff for designating something “gluten-free.”
However, when I tested Jack Daniel’s whiskey and Bombay Sapphire gin, both tested “high-gluten,” meaning testing positive for gluten residues above 20 ppm. And “high gluten” could mean a substantial exposure (though not quantified above the 20 ppm cutoff).
Please do not regard these observations as a criticism of the makers of these spirits, as neither makes any claim about being gluten-free. But I believe it at least calls into serious question about how safe such spirits really are, distillation or no, given that, at least in these two instances, they test for “high-gluten.”
In future, I will be testing some vodkas, such as Tito’s that is distilled six times that has indeed caused many to claim that it is gluten-free.