Isohumulone

From Wikipedia, the free encyclopedia

Isohumulones are compounds that contribute to the bitter taste of beer. The bitterness of beer is measured according to the International Bitterness Units scale, with one IBU corresponding to 1 part per million of isohumulone. When beer is exposed to light, these compounds can be decomposed in a reaction catalyzed by riboflavin, creating 3-methylbut-2-ene-1-thiol, a thiol which causes beer to develop a "skunky" flavor.