27 CFR § 21.124 - Quassin.

---
identifier: "/us/cfr/t27/s21.124"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "27 CFR § 21.124 - Quassin."
title_number: 27
title_name: "Alcohol, Tobacco Products and Firearms"
section_number: "21.124"
section_name: "Quassin."
chapter_name: "ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY"
subchapter_number: "A"
subchapter_name: "ALCOHOL"
part_number: "21"
part_name: "FORMULAS FOR DENATURED ALCOHOL AND RUM"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "5 U.S.C. 552(a); 26 U.S.C. 5242, 7805."
regulatory_source: "T.D. ATF-133, 48 FR 24673, June 2, 1983, unless otherwise noted."
cfr_part: "21"
---


# 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]