A proprietor is required to perform periodic gauges of the spirits, wines, and alcoholic flavorings at the plant. A proprietor must have accurate and readily usable gauging and measuring equipment as required by this part and part 30 of this chapter. At any time, TTB may require that the proprietor's gauges be performed in the presence of, and be verified by, a TTB officer. In addition, TTB may disapprove the use of any equipment, or the proprietor's means of gauging, if TTB finds that it is not sufficiently accurate or suitable for the gauges and measurements to be made.
27 C.F.R. §19.282
26 U.S.C. 5006 , 5204