(R)-Linalool als Schlüsselaromastoff für das Hopfenaroma in Bier und sein Verhalten während der Bieralterung

Within the scope of this assignment it could be shown that the chirale distribution of Linalool in aroma hops starting with raw hops up to all conventional hop products stays almost stable at 94 % R-Linalool. In beer considerably lower amounts of R-Linalool are found. A racemisation during the brewing process is thought to be the cause. Hereby the degree of racemisation obviously depends considerably on the type of hopping. In the course of beer staling racemisation continues with the overall amount of Linalool remaining constant. As a result a flavour loss is detectable also by organoleptic testing. A main factor for the transformation from (R)-Linalool into (S)-Linalool during beer staling may be the pH.- Bitter compounds undergo changes during beer staling that are reflected in an organoleptical and analytical decline of the intensity and quality of the beer bitterness.