Jack Daniels charcoal mellows their whiskey drop by drop, then let it age in our their own handcrafted barrels. They do not follow a calendar. Their Tennessee Sippinâ Whiskey is ready only when their tasters say it is. They use their senses, just like Jack Daniel himself did. In fact, more than a century later, the Tennessee Whiskey is still judged the same way. By the way it looks. By the way it smells. And, of course, by the way it tastes.