Ex-bourbon refers to barrels that have previously held bourbon whiskey. After the bourbon is aged and bottled, these barrels can be reused for aging other spirits, such as scotch, rum, or tequila. The residual flavors from the bourbon can impart unique characteristics to the new spirit, enhancing its complexity. Using ex-bourbon barrels is a common practice in the spirits industry. The barrels are often made from American oak, which contributes to the flavor profile of the aged spirit. This method allows distillers to create distinctive products while also promoting sustainability by reusing barrels.