Influence of hop harvest date of the 'Mandarina Bavaria' hop variety on the sensory evaluation of dry-hopped top-fermented beer

To impart a special hop aroma to beer, dry-hopping is a technique that is becoming more and more popular with commercial breweries. Nevertheless, until now little was known about the factors that influence the reproducibility (and consistent product quality) of dry-hopping with flavour varieties. One factor that could influence the sensory impressions and aroma profile compositions of dry-hopped beers is the hop harvest date. Therefore, to determine the effects of different harvest dates of the flavour variety 'Mandarina Bavaria' on the aroma of top-fermented beer, laboratory-scale dry-hopping trials were performed. Besides tasting sessions of brewed beers, relative quantities of selected hop-derived, as well as beer-originated aroma compounds, were investigated by headspace-solid-phase microextraction-gas chromatography-mass spectrometry. Duo-trio tests between the beers hopped with pellets of different harvest dates showed no significant differences (a = 0.05) between them. In addition, these beers had similar profiles in a five-point profile tasting scheme. On the other hand, relative concentrations of some hop-derived aroma compounds - especially myrcene, which is known to be able to contribute to beer flavour - increased corresponding to a later harvest date, while beer originated volatiles were not different between the beers. Analytical results combined with the results of sensory evaluations led to the conclusion that the harvest date of Mandarina Bavaria was not a dominant factor in the dry-hopping aroma of top-fermented beers. High amounts of fermentation by-products are likely responsible for masking effects resulting in no sensory distinctness between the samples with different hop aroma compound concentrations. Copyright (C) 2016 The Institute of Brewing & Distilling