Two glasses of bourbon against black
What Is Straight Bourbon?
According to the U.S. Alcohol and Tobacco Tax and Trade Bureau (TTB), there are certain criteria that a bourbon bottle must meet to be labeled as "straight bourbon whiskey."
The bottle must be made in the U.S., have at least 51% corn in its mash bill, have no colorings or flavorings added, and can’t be mixed with any other kinds of spirits.
The bottle also can’t exceed 160 proof during distillation and it must have aged for at least two years in new, charred oak barrels. For regular bourbon, there is no aging mandate.
You can find bottles on the market that have aged for as little as three months before being sold, but with a "straight bourbon" label, you can be confident it was properly aged.
You may also come across a "bottled-in-bond" label, which is a sub-type of straight bourbon that has to age for at least four years, giving it a more pronounced and refined flavor.
While straight bourbon can't be mixed with other flavors or spirits, it can be blended with other straight bourbons, so long as they are distilled within the same state.
This rule guarantees a certain level of consistency and purity. No matter how complicated they may seem, all the rules are to help differentiate bottles of bourbon.