Absolute Configuration of Beer′s Bitter Compounds.

During the beer brewing process, bitter tasting cis and trans iso‐α‐acids are generated from the precursor α‐acids found in hops. The absolute configurations of the α‐acid (−)‐humulone and several of its derivatives have now been elucidated by X‐ray crystallography, thus resolving decades of confusion over the humulone isomerization mechanism. [ABSTRACT FROM AUTHOR]