[Code of Federal Regulations]
[Title 27, Volume 1]
[Revised as of January 1, 2008]
From the U.S. Government Printing Office via GPO Access
[CITE: 27CFR21.124]

[Page 554]
 
            TITLE 27--ALCOHOL, TOBACCO PRODUCTS AND FIREARMS
 
 CHAPTER I--ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE 
                                TREASURY
 
PART 21_FORMULAS FOR DENATURED ALCOHOL AND RUM--Table of Contents
 
                Subpart E_Specifications for Denaturants
 
Sec.  21.124  Quassin.

    (a) Quassin is the bitter principle of quassia wood (occurring as a 
mixture of two isomeric forms). It shall be a good commercial grade of 
purified amorphous quassin, standardized as to bitterness.
    (b) Bitterness. An aqueous solution of quassin shall be distinctly 
bitter at a 1 to 250,000 dilution. To test: Dissolve 0.1 gram of quassin 
in 100 ml of 95 percent alcohol, then dilute 4 ml of the solution to 
1,000 ml with distilled water, mix well and taste.
    (c) Identification test. Dissolve about 0.5 gram of quassin in 10 ml 
of 95 percent alcohol and filter. To 5 ml of the filtrate, add 5 ml of 
concentrated hydrochloric acid and 1 mg of phloroglucinol and mix well. 
A red color develops.
    (d) Optical assay. When 1 gram of quassin (in solution in a small 
amount of 95 percent alcohol) is dissolved in 10,000 ml of water, the 
absorbance of the solution in a 1 cm cell at a wavelength of 258 
millimicrons shall not be less than 0.400.
    (e) Solubility. When 0.5 gram of quassin is added to 25 ml of 190 
proof alcohol, it shall dissolve completely.

[T.D. ATF-133, 48 FR 24673, June 2, 1983. Redesignated by T.D. ATF-442, 
66 FR 12854, Mar. 1, 2001]