(a) Approved formulas. A proprietor must denature spirits according to an approved formula listed in part 21 of this chapter.

(b) Alternate formulas and denaturants. If a proprietor wishes to denature spirits by using an alternative formula or a different denaturant, the proprietor must apply to TTB for authorization. A proprietor must receive written approval from the appropriate TTB officer before denaturing spirits using an alternative formula or a different denaturant. See also §§ 21.5 and 21.91 of this chapter for additional requirements that apply in these circumstances.