Jack Daniel’s is a blend of four whiskeys of different ages. The youngest whiskey is at least 4 years old, while the oldest whiskey in the blend is over 7 years old. The Jack Daniel’s blend is made with 80% corn, 12% rye, and 8% barley. The water used to make Jack Daniel’s comes from a spring on the distillery property. Product description. Single Barrel Select layers subtle notes of caramel and spice with bright fruit notes and sweet aromatics for a Tennessee Whiskey with one-of-a-kind flavor. Yes, whiskey is gluten-free, thanks to the distillation process used to make it. The Celiac Disease Foundation concluded that it can safely be considered gluten-free o7ZrR.