CFR > Title 27 - Alcohol, Tobacco Products and Firearms > CHAPTER I—ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY > SUBCHAPTER A—LIQUORS (parts 1 to 31) > PART 21—FORMULAS FOR DENATURED ALCOHOL AND RUM > SUBPART E—Specifications for Denaturants (§21.91 to §21.133) > 21.108—Ethyl ether.