27 CFR § 21.43 - Formula No. 18.

(a) Formula. To every 100 gallons of alcohol of not less than 160 proof add:

One hundred gallons of vinegar of not less than 90-grain strength or 150 gallons of vinegar of not less than 60-grain strength.

(b) Authorized uses.

(1) As a raw material:

511. Vinegar.

(2) Miscellaneous uses:

812. Product development and pilot plant uses (own use only).