Caryophyllene is a bicyclic sesquiterpenoid hydrocarbon and is a constituent of many plant essential oils. Essential oils are the principal aroma components of hop, and constitute 0.5% to 3.0% (v/w) of the whole hop cone; terpenoids are abundant in this fraction. The composition of essential oils is characteristic of the hop genotype and, together with that of bitter acids and flavonoids, has been used for distinguishing different hop varieties. The major terpenoid components of hop essential oil are the monoterpene myrcene, and the sesquiterpenes α-humulene (old name, α-caryophyllene) and β-caryophyllene (often with iso-caryophyllene). These hydrocarbons are very volatile and do not survive the boiling process, and so their detectable presence in a finished beer would be due to late-hopping in the kettle, dry-hopping, or addition of a “late hop” extract. Essential oils are also lost during the storage of hop cones.

Sesquiterpenes are built up from a molecule called farnesyl diphosphate (FDP), which after elimination of phosphate yields β-farnesene. This compound, via a variety of complex reactions, produces caryophyllene and other related structures. In the hop, sesquiterpene synthase1 (H1STS1) is responsible for the formation of caryophyllene from β-farnesene. While a precursor, β-farnesene itself is not found in all hop varieties. The essential oil fraction in hops can be isolated by steam distillation, where they can be analyzed by a variety of methods, including gas chromatography. The in vitro synthesis of β-caryophyllene was achieved in the 1960s.

β-Caryophyllene is also a main flavor constituent of black pepper, which was used as a beer adulterant in bygone years; it produced “heat” on the palate that the buyer was meant to mistake for alcoholic strength.