What type of oak barrel must bourbon use for its first maturation?

Bourbon must use new charred oak containers for its first maturation.

United States regulations require bourbon to be stored in new, charred oak containers. “New” means the container has not previously held another spirit, while “charred” means its interior has been exposed to flame to create a layer of char. The spirit’s interaction with the toasted wood beneath that layer helps provide colour and flavour.

This rule is one reason bourbon barrels are widely reused after bourbon is bottled. Scotch whisky producers, Irish whiskey makers, rum producers, and others often value these ex-bourbon casks because they still contain useful oak compounds and can contribute vanilla, caramel, coconut, and gentle spice notes.

Bourbon does not have to be aged for a particular number of years in general, although straight bourbon must mature for at least two years. A new charred oak barrel is required regardless of whether the bourbon is young or heavily aged.