26 USC 5504 - Operation

(a) General 
Any manufacturer of vinegar qualified under this part may, under such regulations as the Secretary shall prescribe, separate by a vaporizing process the distilled spirits from the mash produced by him, and condense the vapor by introducing it into the water or other liquid used in making vinegar in his plant.
(b) Removals 
No person shall remove, or cause to be removed, from any plant established under this part any vinegar or other fluid or material containing a greater proportion than 2 percent of proof spirits.
(c) Records 
Every person manufacturing vinegar by the vaporizing process shall keep such records and file such reports as the Secretary shall by regulations prescribe of the kind and quantity of materials received on his premises and fermented or mashed, the quantity of low wines produced, the quantity of such low wines used in the manufacture of vinegar, the quantity of vinegar produced, the quantity of vinegar removed from the premises, and such other information as may by regulations be required. Such records, and a copy of such reports, shall be preserved as regulations shall prescribe, and shall be kept available for inspection by any internal revenue officer during business hours.