A. GAHR (1), A. Forster (2); (1) Hopfenveredlung St. Johann GmbH & Co. KG, Train-St. Johann, Germany; (2) HVG Hopfenverwertungsgenossenschaft e.G., Wolnzach, Germany
Friday, October 9
For some time there have been observations that hop aroma in bottled beer is subject to sensory changes upon aging. Linalool is considered one of the major hop aroma contributors, and contradictory information on the aging behavior of linalool can be found in the literature. As linalool is a chiral substance it occurs in two enantiomers R- and S-linalool. Most laboratories measure the total linalool content only, but there is a big difference in the aroma contribution of R- and S-linalools due to their different flavor thresholds in beer. GC data from several trial series were collected and evaluated to find out how linalool and its enantiomers behave during beer aging at different temperatures in late- and dry-hopped beers. While the S-linalool content increases, R-linalool decreases and the R-linalool ratio that typically makes up about 90% of the total linalool in fresh beers decreases as well. This may be one of the reasons for the change in hop aroma while beer ages.
Andreas Gahr was trained on the job as a brewer and maltster at the Augustiner Brewery, Munich, Germany. He received a brew master degree from the Technical University Munich-Weihenstephan in 1994 and worked for another four years at the university for the Chair of Brewing Technology I. Since 1998 Andreas has been the head of the Research Brewery St. Johann, which belongs to the hop processing company of Hopfenveredlung St. Johann GmbH & Co. KG and deals with all kinds of hop-related brewing trials and product development, as well as technological and raw material trials for suppliers and the whole brewing industry. In 2010 he received, along with his co-authors, the MBAA Inge Russel Best Paper Award.