27 C.F.R. § 25.41 Measuring system required.
Title 27 - Alcohol, Tobacco Products and Firearms
The brewer shall accurately and reliably measure the quantity of beer transferred from the brewery cellars for bottling and for racking. The brewer may use a measuring device, such as a meter or gauge glass, or any other suitable method. (Sec. 201, Pub. L. 85–859, 72 Stat. 1395, as amended (26 U.S.C. 5552))
Title 27: Alcohol, Tobacco and Firearms
PART 25—BEER
Subpart E—Measurement of Beer
§ 25.41 Measuring system required.