Ask A Whiskey Writer: How Long Does Bourbon Have To Age? (2024)

When it comes to bourbon, there’s a long list of official legal rules that define the “native spirit” of the United States. While I break down exactly what those rules are here — in another Ask A Whiskey Writer post — I’m going to focus on one facet today: age. So how long does bourbon actually have to age in new oak to be classed as bourbon whiskey?

To understand that question, you need to understand the various bourbon whiskies you see on the shelf. More often than not, you’ll see whiskey labeled as either “Bourbon Whiskey” or “Straight Bourbon Whiskey” and there is a legal reason for that. Let me lay out the labeling by the “time in barrel.”

• 1 millisecond to under 2 years — This is the length that whiskey has to age to be called “Bourbon” or “Bourbon Whiskey.” That’s because standard “bourbon” regulation has no minimum age requirement beyond the very vague “aged in new oak.” Legally, the moment a drop of corn-fueled American whiskey touches new oak, it becomes bourbon whiskey.
• 2 years or more — This is the minimum age for a bourbon to be labeled as a “Straight Bourbon Whiskey“. If a straight bourbon whiskey is under four years of age, then there needs to be an age statement somewhere on the bottle.
• 4 years or more — This is the minimum age for a bourbon to be labeled as a “Bottled In Bond Straight Bourbon Whiskey” — a sub-category of bourbon often referred to as “the good stuff”. Bottled in bond straight bourbon whiskeys also need to be proofed to exactly 100-proof or 50% ABV.
• Age statements (8-year, 10-Year, 15-Year, 20-Year, etc.) — Any age statement must be the age of the youngest straight bourbon whiskey in the batch/blend. Unless it’s a single-barrel expression, all bourbon is a blend of bourbon barrels. In some cases, there can be far older barrels in big batches of high-age bourbon whiskeys. For instance, Michter’s 10-Year Straight Bourbon Whiskey often is made with barrels over 12 to 15 years old. But since they don’t have a 12 or 15-year expression, those barrels are bottled as their 10-year bourbon. Eagle Rare 10-Year Straight Bourbon Whiskey will also have 12-year and above barrels in its blend too but since the youngest barrels are always at least 10 years old, it’s a 10-year expression.

To sum up: For a corn-based American whiskey to be called a bourbon it has to age for a millisecond in new oak. But that’s only the beginning. From there, these are the year points that are important: 2 years for straight bourbon, 4 years for bottled in bond, and then it just goes up and up (with age statements based on the youngest bottle in the batch)– usually tapping out around 20-25 years. After that, bourbon gets prettttty over-oaked in most cases that we know of.

As a final aside, you can have a 50-year-old bottle of bourbon (like your grandparent takes it off the shelf where it has awaited this day in a crystal decanter tucked in a secret closet) but it is only 50 years old as a bottle. That bourbon was not aged 50 years. Bourbon is aged in a barrel and that process ends, full stop, when it is bottled. That can add a little confusion but it’s quickly sorted — the years that count toward “aging” are the years in the barrel.