Technical Session 01: Hops I Session
Daniel C Sharp, Oregon State University, Corvallis, OR USA
Co-author(s): Yanping Qian, Shaun Townsend, and Thomas Shellhammer, Oregon State University, Corvallis, OR, USA
ABSTRACT: Hop chemical composition changes, in particular
aroma development, during plant maturation are part of a rapid and
dynamic process that requires a comprehensive, in-depth chemical and
sensory analysis to maximize characteristics of interest to brewers. The
complex aroma chemistry associated with hops in beer has been a
confounding variable for practical brewers, and a deeper understanding
of hop aroma development during cultivation is needed. This presentation
discusses results and conclusions from a two-year study and compares
these results with other studies that have examined location and harvest
time and their effect on brewing quality. The effect of harvest date
and location on and a variety of key chemical components of Willamette
and Cascade hops were investigated for the 2010 and 2011 growing
seasons. Hops were harvested at three time points within a 3-week
interval (early, normal, and late), from three different farms in the
Willamette Valley, Oregon, and then analyzed for moisture, hop acids
content, total oil content, and essential oil composition. The response
of analytes was dependent on the variety being examined, its location
within the Willamette Valley, as well as the time of harvest. Hop acids
did not change appreciably during plant maturation, while hop oil
content increased hyperbolically to a plateau as the hops aged on the
bine. Increases in oil quantity were strongly correlated (r >
0.80) with increases in alpha-pinene, beta-pinene, myrcene, limonene,
methyl heptanoate, linalool, and eudesmol concentrations. Growing
location within the Willamette Valley had a significant effect on oil
concentrations for each variety at each time point, thus suggesting that
individual grower practices and local environmental influence hop
chemical composition.
Daniel Sharp is a master’s student in the
Food and Fermentation Science program at Oregon State University. His
research is currently focused on hop studies being conducted in Thomas
Shellhammer’s lab. Daniel’s primary area of study is the aroma compounds
in hops and beer. Prior to joining the Food Science program at OSU,
Daniel earned a B.A. degree in both Spanish and adventure leadership at
the University of Oregon. After graduation he lived and worked in South
America, first as a mountain guide in Venezuela and later as a brewer at
the Center of the World Brewery, Ecuador’s only microbrewery at the
time.
VIEW PRESENTATION 2
