27 C.F.R. § 71.126
On written application by a party to a proceeding, the attendance and testimony of any person, or the production of documentary evidence in proceedings instituted under this part may be required by personal subpoena (Form 5600.10) or by subpoena duces tecum (Form 5600.11). Application should be addressed to, and subpoenas should be issued by, the administrative law judge before whom the proceedings are pending, but may be issued by the appropriate TTB officer or by the Administrator, if the administrative law judge is unavailable. Both the application and the subpoena shall set forth the title of the proceedings, the name and address of the person whose attendance is required, the date and place of his attendance and, if documents are to be produced, a description thereof; and the application must have reasonable scope and specify as exactly as possible the documents required, if any, and show their general relevance. Subpoenas shall be served in person. When issued on behalf of the United States, service shall be made by an officer, employee, or agent of the Treasury Department; when issued on behalf of a permittee or applicant, service shall be made by any person who is not a party to the proceeding and is not less than 18 years of age.
27 C.F.R. § 71.126
49 Stat. 977, 72 Stat. 1372; 27 U.S.C. 202 , 26 U.S.C. 5274