27 C.F.R. § 28.144 – Export marks.

(a) General Requirement. In addition to the marks and brands required to be placed on containers of beer or beer concentrate under the provisions of part 25 of this chapter, the brewer shall mark the word “Export” on each container or case of beer, or the words “Beer concentrate for export” on each container of beer concentrate, before removal from the brewery for any exportation authorized under this subpart.
(b) Exceptions. A brewer need not apply the mark “Export” on cases of beer being exported under the following circumstances:
1. (1) When beer is being directly exported by the brewer, and the brewer can furnish documentation (such as an ocean or air freight bill of lading, or a foreign landing certificate) that the beer was directly exported to a foreign country;
2. (2) When cased beer is transferred from a brewery to a foreign-trade zone for export or for storage pending exportation; or
3. (3) When cased beer is exported to the military.
  (Sec. 309, Tariff Act of 1930, 46 Stat. 690, as amended (19 U.S.C. 1309); sec. 3, Act of June 18, 1934, 48 Stat. 999, as amended (19 U.S.C. 81c); sec. 201, Pub. L. 85-859, 72 Stat. 1334, as amended (26 U.S.C. 5053))