ANALYSIS OF HOP OIL BY GAS-LIQUID PARTITION CHROMATOGRAPHY

Abstract

Apparatus for analysis of hop aromatic oil by gas-liquid partition chromatography is described and analyses are reported for the principal components in the oils from commercial samples of 16 varieties of hops. Distinct peaks are obtained for as many as 13 components in the whole oil, but chromatography of the oxygenated fraction alone indicates that many additional components are present in small amounts. Myrcene and humulene comprise 70–80% of most oils but methyl nonyl ketone and two other compounds, believed to be β- and γ-caryophyllene, are present in substantial quantities. Analyses of the ã-acid fractions of these hops are also reported and a highly significant correlation has been found between the myrcene content of the oil and the cohumulone content of the ã-acid fraction, and also between the humulene content of the oil and the humulone content of the ã-acid fraction. Oils from Continental European hops generally have a low myrcene and high humulene content while the reverse is true of North American hops.