Influence of different fermentation conditions on the analytical and sensory properties of craft beers: Hopping, fermentation temperature and yeast strain

The influence of the hopping method (boiling stage hopping or dry hopping), the fermentation temperature (12 and 18 °C), and the yeast strain (five different yeasts) on the physical-chemical characteristics (bitterness, color, alcohol content), the phenolic content, the volatile compounds, as well as the sensory profile of beers, has been studied. The hopping method was much more influential than temperature and yeast strain, however, its influence on volatile content clearly depended on the fermentation temperature, with a higher content of volatile compounds, when a higher fermentation temperature was employed. For phenolic compounds, dry hopping produced less polyphenol-rich beers, regardless of the fermentation temperature. Sensorily, it resulted in more floral and fruity beers than those produced by boiling stage hopping, which exhibited a more intense toasted aroma. Concerning yeast strain, no relationship could be established between the type of commercial yeast (bottom or top-fermenting) and the resulting volatile content.