Correlation of Sensory and Instrumental Data in Elucidating the Effect of Varietal Differences on Hop Flavor in Beer. Terry L. Peppard, Sharon A. Ramus, Cathy A. Witt, and K. J. Siebert, The Stroh Brewery Company, Detroit, MI 48207. J. Am. Soc. Brew. Chem. 47:0018, 1989.

There is plentiful evidence that both the composition of the essential oil of hops and hop flavor in beer are influenced by variety. However, correlating these analytical and sensory data, and relating them to the varietal factor, are difficult because many of the major constituents of hop oil are not normally found in finished beer. The present studies sought to differentiate between a number of hop varieties on the basis of flavor attributes used to describe hoppy flavor in beer and to search for correlations between the latter and individual hop oil-derived flavor constituents found in beer. For this purpose, a series of pilot-scale beers was brewed using four domestically grown U.S. hop varieties and four imported European hop varieties. Sensory and compositional data were collected using experimental protocols specially devised for the purpose and were examined using a number of multivariate statistical techniques. The beers brewed with domestic hops were readily distinguishable from those brewed with imported hops, on the basis of either sensory or instrumental data. Using the technique of partial least squares analysis, a number of strong statistical correlations were noted to exist between particular hoppy flavor attributes and certain hop oil components.

Keywords: Analysis of variance, Factor analysis, Gas chromatography, Hop flavor, Mass spectrometry, Partial least squares analysis