AbstractSixteen basic heterocyclic compounds have been identified by g.c.‐m.s. after careful extraction of a flavour essence from an English beer. They include the following that have not previously been reported as beer constituents: pyridine, 2‐acetylpyridine, 3‐acetylpyridine, pyrazine, methylpyrazine, 2,3‐dimethylpyrazine, 2,5‐dimethylpyrazine, 2,6‐dimethylpyrazine, 2‐ethyl‐5‐ (and/or 6‐) methylpyrazine, trimethylpyrazine, 2‐ethyl‐3,5‐dimethylpyrazine, 2‐ethyl‐3,6‐dimethylpyrazine, 2‐ethyl‐5,6‐dimethylpyrazine, 6,7‐dihydro‐5H‐cyclopentapyrazine, 2‐methyl‐6,7‐dihydro‐5H‐cyclopentapyrazine, and thiazole. The minimum total concentration of basic compounds in the beer was estimated to be 10 mg/kg.