CFR /  Title 27  /  Part 19  /  Sec. 19.647 Authorized operations.

After approval of an application by TTB, a plant qualified for the production of vinegar may only:

(a) Produce vinegar by the vaporizing process; and

(b) Produce distilled spirits of 30[deg] of proof or less for use in the manufacture of vinegar on the vinegar plant premises. (26 U.S.C. 5501)