Identification of U.S.-Grown Hop Cultivars by Hop Acid and Essential Oil Analyses¹

1 Presented at the 53rd Annual Meeting, Cincinnati, OH, June 1987.

Abstract

The purpose of this research was to identify hop acid and essential oil characteristics that could be used to identify hop cultivars grown in the United States. Ten commercial cultivars were analyzed: Cascade, Chinook, Cluster, Eroica, Fuggle, Galena, Nugget, Olympic, Perle, and Willamette. One group of samples represented production between 1983 and 1987 at the Washington State University Irrigated Agriculture Research and Extension Center in Prosser, WA; the second group represented the 1986 commercial production from the Washington, Oregon, and Idaho hop-growing regions. After each crop year, fresh hop samples were analyzed for α- and β-acid concentrations, cohumulone ratio, colupulone ratio, and essential oil composition. Cohumulone and colupulone ratios and six essential oil component ratios were found to be useful in cultivar identification. The essential oil components suggested for use in cultivar identification were caryophyllene, farnesene, humulene, methyl-4-decenoate, methyl decanoate, β-selinene, 2-tridecanone, α-ylangene, and two unknown peaks. From the analytical data for hop acids or essential oils, dichotomous keys were developed to identify the 10 cultivars based on each. All cultivars could be distinguished using either identification key.

• Alpha-acid
• Beta-acid
• Cohumulone
• Colupulone
• Humulus lupulus L