Proof of distillation.
Proof of distillation. The composite proof of the spirits when the production gauge is made, or, if the spirits are reduced in proof prior to the production gauge, the proof of the spirits prior to that reduction, unless the spirits are subsequently redistilled at a higher proof than the proof prior to reduction.
Source
27 CFR § 19.1
Scoping language
As used in this part, the following terms shall have the meanings indicated unless either the context in which they are used requires a different meaning, or a different definition is prescribed for a particular subpart, section, or portion of this part: