12:00 – 12:25

Transfer of aroma from hops to beer: molecules that come and molecules that go

Hops (Humulus lupulus L.) impart distinctive aromas and bitterness to beers due to their rich composition in essential oils and acid resins. This study investigated the transfer of aroma compounds from the different forms of hops (fresh, dry, pellets) to the finished product, focusing on the Chinook and Cascade varieties. Single hopped Pale Ale (5% ABV), IPA (6.5%) and DDH IPA (7.2%) were brewed with different hopping techniques. Gas chromatographic analyses enabled the identification of more than 100 aroma molecules and the evaluation of their concentration levels. The results showed a good transfer of key compounds such as beta-pinene, beta-myrcene, alpha-caryophyllene, linalool and beta-farnesene, with significant differences depending on the hop variety, its form and the time of addition during production. The dry hopping technique in the final stages of fermentation favoured a better preservation of aromas. Geraniol, on the other hand, showed greater degradation. This study provides valuable information for optimising the transfer of desired aroma compounds into beers, depending on the brewing style.

Speaker:
Irene Lucchetta, Research Fellow, University of Padua