Hops are requisite materials that impart bitterness, hoppy aroma, and flavor to beer. The purpose of this study was to understand the effect of harvest time and pruning date on aroma characteristics of beer for Saaz hops from the Czech Republic using quantitative descriptive analysis and two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) measurements. Hop teas were used for an alternative simplified sensory test to estimate the hop aroma profiles in beer. The key compounds in hops that are responsible for changes in hop aroma with harvest time and pruning date were quantitated with GC×GC/TOF-MS and multivariate analyses. Scores for aroma characteristics, such as floral, fruity, and citrusy characteristics, significantly increased for later harvest times and middle pruning dates. Additionally, the contents of certain compounds, such as Z-citral, linalool, and heptatonic acid, were positively correlated with the intensities of floral, fruity, and citrusy characteristics, whereas E-3-hexen-1-ol and octanoic acid were negatively correlated with these characteristics. The contents of these compounds were positively or negatively correlated with harvest time and pruning date. Therefore, the aroma profiles for hop teas or beer could be controlled by altering the harvest time and pruning date. Keywords: Beer, Hop aroma, GC×GC/TOF-MS, Harvest time, Pruning date, Saaz
Supplementary Figure 1 shows humulone (%) and linalool (mg/kg) distribution in Czech Saaz hops from 2010 and 2011.
Supplementary Figure 2 shows the relationship between pruning and flowering dates for Czech Saaz hops grown in 2012.
Supplementary Figure 3 is a growing area map showing where the cultivation trials for the Saaz hops were carried out.
