Hopping technology in relation to beer bitterness consistency and flavor stability

The fate of alpha-acids, iso-alpha-acids, and their chemically modified variants was monitored in pilot brews as a function of hopping regime and beer aging. HPLC analysis indicates that a-acids, iso-a-acids, and dihydroiso-alpha-acids in beer are not stable during forced aging. This is reflected further in the sensory performance of these beers. Beer exclusively bittered with tetrahydroiso-alpha-acids was completely stable, in terms of hop components, under the experimental conditions employed. In addition, overall flavor stability was significantly improved. These results provide further evidence that hop-derived bitter acids, including the light-stable dihydroiso-alpha-acids, could play an important role in beer flavor deterioration during storage.