Daniel M. Vollmer and Thomas H. Shellhammer.
Department of Food Science and Technology, Oregon State University,
Corvallis, OR 97331, U.S.A.
Dry hopping is a technique widely practiced by brewers to add hop
aroma to beer. The technique can also be used on a small scale to
evaluate the aroma potential of hops in beer. This format has practical
uses for hop breeders, brewers, and hop suppliers. Our investigations of
small-scale dry hopping have identified a significant amount of
variability in the aroma intensity and profile of dry-hopped beers as
measured by sensory analysis. A systematic approach at reducing the
variability in a pilot-scale dry-hopping process was successful in
reducing this variability. This method entailed improved whole-cone hop
sampling techniques, increasing the volume of beer that was dry hopped,
and blending two single dry-hop events during filtration for a single
treatment. In addition to these process changes, oxygen control acted as
an appropriate quality assurance strategy and appeared to contribute to
the reduced variability in the aroma intensity of dry-hopped beer
prepared on a pilot scale. The outputs of this work suggest that
small-scale dry-hop evaluations are prone to variability and that simple
modifications to account for variation in hops and beer handling can
reduce this variability for the purposes of pilot-scale evaluations.
Keywords: Blending, Dissolved oxygen, Dry hopping, Pilot