19 CFR § 159.4 - Alcoholic beverages.
(a) Quantities subject to duties. Customs duties and internal revenue taxes on alcoholic beverages provided for in headings 2207 and 2208, Harmonized Tariff Schedule of the United States (HTSUS), (19 U.S.C. 1202), and subject to internal revenue taxes shall be collected only on the number of proof gallons and fractional parts thereof, entered or withdrawn for consumption. No internal revenue tax shall be collected on distilled spirits in bulk which have been transferred to Internal Revenue bonded premises in accordance with § 141.102(b) of this chapter. Customs duties and internal revenue taxes on alcoholic beverages other than subheadings 2206.00.30 and 2206.00.90, HTSUS, and distilled spirits provided for in headings 2207 and 2208, shall be collected only on the number of wine gallons and fractional parts thereof, entered or withdrawn for consumption.
(b) Computation of duties. In the computation of Customs duties on alcoholic beverages provided for in headings 2207 and 2208 (19 U.S.C. 1202), which are also subject to internal revenue taxes, the methods prescribed for the computation of internal revenue taxes on such beverages shall be followed. The following methods apply to the specific beverages shown:
(1) Distilled spirits. The quantity of distilled spirits imported in barrels, kegs, or similar containers shall be ascertained in accordance with the regulations of the Bureau of Alcohol, Tobacco and Firearms. Where distilled spirits are imported in bottles, jugs, or similar containers, Customs duties and taxes shall be collected on the exact quantity contained in each case or other outer container, fractional parts of a gallon being carried out to three decimal places utilizing the proof gallon method of computation.
(2) Wine. Customs duties and taxes on wines shall be on the basis of a wine gallon of liquid measure equivalent to 231 cubic inches and shall be paid proportionally on all fractional parts of a wine gallon. Fractions of less than one-tenth gallon shall be converted to the nearest one-tenth gallon, and five-hundredths gallon shall be converted to the next full one-tenth gallon.
(3) Beer and similar fermented beverages. Customs duties and taxes on beer, ale, porter, stout, and other similar fermented beverages, including sake, of any name or description containing one-half of 1 percent or more of alcohol by volume, brewed or produced from malt, wholly or in part, or from any substitute therefor, shall be collected in accordance with section 5051(a), Internal Revenue Code of 1954 (26 U.S.C. 5051(a)).