Code of Federal Regulations Title 27. Alcohol, Tobacco Products and Firearms § 27.31.201 Refilling of liquor bottles

(a) Place in any liquor bottle any distilled spirits whatsoever other than those contained in that bottle at the time of closing under the provisions of 26 U.S.C. chapter 51;  or

(b) By the addition of any substance whatsoever to any liquor bottle, in any manner alter or increase any portion of the original contents contained in that bottle at the time of closing under the provisions of 26 U.S.C. chapter 51.