Epsilon Archive for Student Projects

Abstract

Swedish heritage hop varieties represent a relatively unexplored resource in modern brewing, particularly regarding their aroma potential and chemical composition. The aim of the present study was to investigate selected Swedish heritage hops in beer brewing and evaluate differences in hop-derived compounds following dry hopping during fermentation. A single wort was divided into twelve fermentation vessels representing six treatments conducted in biological duplicate, including five dry-hopped beers and one non-dry-hopped control. Brewing performance was monitored throughout fermentation and maturation. α- and β-acids in hop material and finished beer were quantified using HPLC, while sensory evaluation was performed using a semi-trained consumer panel assessing hop-related aroma attributes. Selected hop-derived terpenes were analyzed in hop material, post dry-hop beer and finished beer using GC-FID.

The investigated hop varieties displayed clear differences in α- and β-acid composition. Korsta exhibited the highest β-acid content and the lowest α/β-acid ratio among the investigated varieties, while several Swedish cultivars showed elevated residual α-acid concentrations in beer compared with the non-dry-hopped control, indicating transfer of hop-derived compounds during dry hopping. Estimated apparent dry-hop α-acid recovery ranged between approximately 4–9%, while the Magnum kettle addition showed an apparent utilization of approximately 29%, consistent with previously reported brewing ranges.

Sensory analysis revealed substantial variation among assessors and no statistically significant differences between treatments were detected by one-way ANOVA (p > 0.05), although tendencies were observed for citrus-related aroma and overall hop intensity. GC-FID analysis indicated that hydrocarbon terpenes such as β-myrcene, trans-caryophyllene and γ-terpinene were primarily detected in hop material, whereas linalool and geraniol persisted throughout the brewing process and were detected in finished beer samples. Limonene was also detected in several beer samples, indicating partial transfer of hop-derived monoterpenes into the final product.

The results demonstrate that Swedish heritage hop varieties possess distinct chemical characteristics and contribute measurable differences in hop-derived compounds following dry hopping. The findings support continued investigation of Swedish heritage hops as a brewing resource and highlight the importance of compound-specific behavior during aroma transfer from hop material to finished beer.