What Makes Bourbon Different From Other Whiskey?

Bourbon is one of the few spirits in the world defined almost entirely by federal law rather than tradition alone. Under U.S. regulations, bourbon must be made in the United States (not just Kentucky, despite the popular myth), from a mash bill of at least 51% corn, distilled to no more than 160 proof, entered into new charred oak barrels at no more than 125 proof, and bottled at a minimum of 80 proof.

That charred, new-oak requirement is the single biggest flavour driver. Unlike Scotch, which is typically aged in used sherry or bourbon casks, bourbon’s barrels are freshly charred every single time, which is what gives bourbon its signature caramel, vanilla, and toasted-oak sweetness. It also means the American bourbon industry effectively supplies the used barrels that much of the Scotch and Irish whiskey world relies on for maturation.

The high corn content also sets bourbon apart on the palate. Corn brings a natural sweetness that rye and malted barley don’t, which is why bourbon tends to taste rounder and sweeter than rye whiskey or Scotch, even before oak influence is considered. Mash bills vary by distillery — a “high-rye” bourbon might use 35% rye for extra spice, while a “wheated” bourbon like Pappy Van Winkle swaps rye for wheat for a softer, more mellow profile.

Age statements matter differently in bourbon than in Scotch. Because Kentucky summers are hot and barrels breathe more aggressively, bourbon matures faster — a 12-year-old bourbon can taste as developed as a 20-year-old Scotch. That’s also why very old bourbons can become over-oaked and bitter, whereas Scotch often needs decades to reach its peak.

If you’re building out a bourbon collection, look for the mash bill, the barrel entry proof, and whether it’s a single barrel or small batch release — all of it tells you what to expect before you even pull the cork.