Which statement is true regarding the aging process of bourbon?

The statement that bourbon must be aged in new oak barrels is accurate and reflects an essential legal requirement for the production of this specific type of whiskey. The law stipulates that to be classified as bourbon, it must be aged in new charred oak barrels. The use of new barrels is critical because it allows the bourbon to extract flavors and compounds from the wood, which contribute to its distinctive character, aromas, and colors. The charring of the barrels creates a layer of charcoal that can filter the spirit and enhance its flavor profile.

In contrast, other options, such as the need for a minimum aging period of five years, are not mandates for all bourbons; only those aged for less than this duration must be labeled accordingly. Bourbon can only be aged in new barrels and not used ones, which directly contributes to the uniqueness of its style. Additionally, aging in stainless steel barrels would not impart the wood-derived flavors and characteristics that are quintessential to bourbon, thus it does not comply with bourbon production regulations.