27 C.F.R. § 30.65
This table may be used to ascertain the weight of any given number of wine gallons (at 60 degrees Fahrenheit) or proof gallons of spirits by multiplying the pounds per gallon by the given number of gallons of the spirits. The table should be especially useful where it is desired to weigh a precise quantity of spirits.
Example. It is desired to ascertain the weight of 100 wine gallons of 190 proof spirits:
6.79434*100 equals 679.43 pounds, net weight of 100 wine gallons of 190 proofs spirits.
Example. It is desired to ascertain the weight of 100 proof gallons of 190 proof spirits.
3.57597*100 equals 357.60 pounds, net weight of 100 proof gallons of 190 proof spirits.
The slight variation between this table and Tables 2 and 3 on some calculations is due to dropping or adding of fractions beyond the first decimal on those tables. This table also shows the weight per wine gallon (at the prevailing temperature) corresponding to each uncorrected reading of a proof hydrometer.
27 C.F.R. § 30.65
Sec. 201, Pub. L. 85-859, 72 Stat. 1358, as amended ( 26 U.S.C. 5204 )