Hop Aroma Component Profile and the Aroma Unit. Gail B. Nickerson, Department of Agricultural Chemistry, Oregon State University, Corvallis 97331-6502, and Earl L. Van Engel, Blitz-Weinhard Brewing Company, Portland, OR 92709. J. Am. Soc. Brew. Chem. 50:0077, 1992.

More than 250 essential oil components have been identified in hops by capillary gas chromatography. The hop aroma component profile (HACP), quantitatively measured as nanoliters per gram of hops (1 ppm, v/w), is composed of 22 of these hop oil compounds that have been reported to affect hop aroma. Similar steam distillation methods were used to measure the HACP of hops, wort, and beer. HACP analysis of seven commercial hop pellet samples (Cascade, Chinook, Cluster, Hallertau, Saaz, Tettnang, and Willamette) were made. It was found that within one variety, the total HACP could vary by as much as 50%. Subsequently, the hop aroma unit, which consists of 1 nl/g (1 ppm, v/w), the sum of the 22 hop oil constituents, was conceived. The hop aroma unit can be used as a standard measure of hop aroma content, just as the bitterness unit is used to measure bitterness.

Keywords: Aroma, Hop, Hop oil