I found this rather interesting. After watching the tutorials on alcholic beverages, someone mentioned to me that wheat was used in the processing of wine. I feel like Columbo! checking out the clues. “Spirits made without any grain such as brandy, wine, mead, cider, sherry, port, rum, tequila and vermouth generally do not contain gluten, although some vineyards use a flour paste to caulk the oak barrels in which wine is aged, and other vineyards use gluten as a clarifying agent (though it's unclear whether gluten remains at the end of the clarification process).” This is from Wikipedia.