Yes, they are. All spirits, even those distilled from grains such as wheat, rye, and barley are gluten-free. That’s because during distillation, the grains containing gluten proteins that provide sugar and starch for fermentation are removed completely, and none of it is carried over into the final product, be that product vodka, whiskey, gin, or any other spirit.
In fact, in August 2020, the FDA ruled that starting in September of the same year, all spirits could be labeled gluten-free if they so choose. As part of the ruling the FDA stated: “[Distillation] removes gluten because gluten does not vaporize. Therefore, there should not be any gluten remaining in the final distilled product. For this reason, a distilled product labeling may bear a ‘gluten-free’ claim and should be safe for people with celiac disease to consume.”
So, even if you don’t see “gluten-free” labeled on a bottle of spirit, you can feel confident that the product is gluten-free. Whether or not that spirit chooses to include the label on the bottle is just a marketing decision.