Preliminary separation of hop oil (from Humulus lupulus L. van Bullion) by physical and chemical methods, followed by programmed gas-chromatography analysis of the individual fractions, revealed the presence of approximately ZOO components. The hydrocarbon fraction (70% of the total oil) contained myrcene (30%), caryophyllene (20%), and humulene (40%), plus some 20 minor componentl (10%). The oxygenated fraction contained a complex mixture of alcohols (2-methys butanol, linalool, nerol, geraniol, nerolidol, etc.), carbonyls (methylnonyl ketone and numerous other methyl ketones, citral and other aldehydes), and esters of carboxylie acids having straight chains, branched chains and unsaturated straight and branched chains. Most of the identifications are based on gas chromatographic retention times and are tentative.* Collaborator, employed by United States Brewers' Association, Inc., with whom this work was conducted co-operatively.Vol. 69, 1983] jahnsen: composition of hop oil