The most well-known style of whiskey produced in the United States is bourbon. It is so popular now, both in the United States and abroad, our distillers can’t make enough of the stuff. Bourbons, like Jim Beam, Wild Turkey, and Maker’s Mark, fit in a category known as “straight whiskeys,” and if you look closely enough on a bourbon label, you’ll see it identified that way.
A straight whiskey must meet strict requirements. It has to be made in the United States (and while nearly all straight bourbon is made in Kentucky right now, it doesn’t legally have to be), and its grain formula, known as the “mash bill,” must contain at least 51% corn. It can’t be distilled higher than 80% alcohol (by volume) or go into the barrel for aging higher than 62.5% alcohol, and has to be aged in new charred oak barrels for a minimum of two years. These requirements are designed to maintain the quality and consistency of bourbon.
Other straight whiskeys, like straight rye whiskeys and straight wheat whiskeys must meet similar requirements. The only difference is that rye or wheat is the main grain (respectively), rather than corn.
If you walk into a bar and ask for a bourbon, there’s a good chance you’ll get Jack Daniel’s. This is probably the biggest misunderstanding in the world of whiskey. It’s a Tennessee whiskey and made just like bourbon—except for one additional step in the process. After the spirit is distilled, and before it is put into charred oak barrels for aging, it is charcoal mellowed through vats of sugar maple charcoal. This changes the flavor profile of the whiskey—which some describe as mellower, gently sweeter, and slightly sooty when compared to bourbon—making it distinctly Tennessee whiskey.
While bourbon has to be made from a mash of at least 51% corn; in reality, it usually is made with 70-80% corn. The remainder consists of rye and malted barley. You can think of rye as the “spice” ingredient of bourbon. It doesn’t have to be used, but it has a significant impact on the flavor profile. If you’ve ever tasted rye bread, then you understand rye’s contribution to bourbon.
But some bourbon producers replace the rye with wheat. Wheat changes the flavor profile in its own way. “Wheated” bourbons, like Maker’s Mark, are less bold and more approachable. Some drinkers like the easy-going style of wheated bourbons, while others enjoy the boldness of more traditional rye-spiced bourbons.