Bourbon a form of whiskey that's considered "America's native spirit" must be made from at least 51% corn, which is a gluten-free grain. However, the rest of the mash that goes into bourbon (up to 49% of the total) generally comes from wheat, barley and rye ... which are, of course, the three main gluten grains.
But does that mean bourbon isn't gluten-free? Depends on whom you ask. Experts disagree on whether people with celiac disease and gluten sensitivity can safely drink bourbon and other alcoholic beverages distilled from gluten grains.
The National Institutes of Health and several major celiac societies in the U.S. and Canada say that distilled alcohol is considered gluten-free because the process of distillation removes the harmful gluten protein.
However, the Celiac Sprue Association recommends that people with celiac disease consume only alcoholic beverages that are not sourced from gluten-based grains ... which would rule out bourbon.
And, the Alcohol and Tobacco Tax and Trade Bureau, which regulates alcoholic beverages in the U.S., ruled in 2012 that beverages made from gluten grains cannot legally carry the claim "gluten-free," since gluten (or fragments of the gluten protein) remaining in such drinks may not be detected easily with existing testing technology (read more about that in Labeling Rules for Gluten-Containing Alcoholic Beverages).
So Should You Drink Bourbon or Not?
The majority of people with celiac or gluten sensitivity don't seem to react to alcohol distilled from gluten grains, but a substantial minority do react ... hence the disagreement between the experts.
It's not clear how many people get sick from these beverages, but it's enough that I urge everyone who's new to the diet to try bourbon and other gluten-grain-containing alcoholic beverages with some major caution, especially at first. I explain more (and tell you what symptoms to look for) in my article Is Alcohol Gluten-Free?
There's one other potential option if you react badly to gluten-grain-based alcohol: I've searched around and found a 100% corn-based bourbon, Hudson Baby Bourbon. Be aware that I haven't tried this bourbon, and it makes no claims to being gluten-free or free of gluten cross-contamination (it's made by a small distillery that also processes gluten grains). But I mention it because it may be an option for some people who crave bourbon but who react to most of those out there.