Changes

| ''cis''-alloisohumulone and ''trans''-alloisohumulone || Iso-alpha acids (''cis'' -isohumulone and ''trans'' -isohumulone) || Y || ? || ''cis''-alloisohumulone was found in trace levels in a Pilsner style beer at all different aging points, but ''trans''-alloisohumulone remained undetected.

| ''trans''-humulinic acid and ''cis''-humulinic acid || Iso-alpha acids (''cis'' -isohumulone and ''trans'' -isohumulone) || Y || No bitterness || Minor levels in wort, but stable through the brewing process. Higher levels were detected in beers aged in oxygen permeable PET bottles versus glass bottles. Humulinic acid content increases over the storage of beer over many years as iso-alpha acids decrease. It has been suggested that the decomposition of iso-alpha acids into humulinic acids over time plays a role in the decrease in perceived bitterness of aged beer. |-| Hydroperoxy-''cis''-alloisohumulones and Hydroperoxy-''trans''-alloisohumulones || Iso-alpha acids (''cis''-isohumulone and ''trans''-isohumulone) || Y || ? || Iso-alpha acids degrade into these in beer that is exposed to oxygen after just 1-2 hours. ''Cis''-isohumulone degrade into hydroperoxy-''cis''-alloisohumulones, while ''trans''-isohumulone degrade into Hydroperoxy-''trans''-alloisohumulones and tricyclohumol. They are also formed during the wort boiling process, but are reduced by 50% during the fermentation process. Hydroperoxy-''trans''-alloisocohumulone increases as beer is stored in bottles over many years (1, 4, and 10 years were measured in one study), while hydroperoxy-''cis''-alloisocohumulone is less stable and decreases. In PET bottles, both types of hydroperoxy-alloisohumulones decreased to zero after 4 years of storage at room temperature. While the degredation of iso-alpha acids into hydroperoxy-alloisohumulones occurs very quickly when in the presence of oxygen, the degradation of hydroperoxy-alloisohumulones occurs much more slowly during storage at room temperature.|-| Hydroxyl-''cis''-alloisohumulones and Hydroxyl-''trans''-alloisohumulones || Hydroperoxy-''cis''-alloisohumulones and Hydroperoxy-''trans''-alloisohumulones || Y || ? || Hydroperoxy-alloisohumulones are further degraded into their respective hydroxyl-alloisohumulones (''cis'' and ''trans'') via metal ions or UV light. Similar to hydroperoxy-alloisohumulones, hydroxyl-''trans''-alloisohumulones slowly increase during storage of bottles at room temperature over many years (1, 4, and 10 years), while hydroxyl-''cis''-alloisohumulones slowly decrease. In PET bottles, both types degrade to nearly 0 (from 0.39 umol/L to 0.08 umol/L) after 4 years at room temperature. When beer is intentionally oxidized, the hydroperoxy-alloisohumulones degrade very quickly over 24 hours into their hydroxyl-alloisohumulones derivatives.