27 C.F.R. § 19.343 Addition of oak chips to spirits and addition of caramel to brandy and rum.
Title 27 - Alcohol, Tobacco Products and Firearms
Oak chips which have not been treated with any chemical may be added to packages either prior to or after filling. When oak chips are added to packages, notation of such fact shall be made on all transaction records. Caramel possessing no material sweetening properties may be added to rum or brandy in packages or tanks. (Sec. 201, Pub. L. 85–859, 72 Stat. 1356, as amended (26 U.S.C. 5201))
Title 27: Alcohol, Tobacco and Firearms
PART 19—DISTILLED SPIRITS PLANTS
Subpart L—Storage
§ 19.343 Addition of oak chips to spirits and addition of caramel to brandy and rum.

