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Hops
,update to summary of aged hop compounds from alpha/beta acids
| Scorpiohumols || Hydroxyl-''trans''-alloisohumulone || Y || ? || Same as Tricyclohumulactol.
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| Tricyclocohumol, Tricyclocohumene, Isotricyclocohumene, Tetracyclocohumol, and Eptitetracyclocohumol || ''Trans''-isohumulone (iso-alpha acid) || Y || Bitterness thresholds in beer as umol/L: 30, 5, 10, 70, 70 (''Trans''-isohumulone is 20). Characterized as "lingering harsh bitterness". || The most abundant oxidation derived hop compounds in aged beer. All are derived from ''trans''-isohumulone, which is the iso-alpha acid that is less stable than ''cis''-isohumulone. ''Trans''-isohumulone degrades into these faster at warmer temperatures and lower pH (no degradation at a pH of 6, slower degradation at a pH of 3, and very fast degradation at a pH of 1). Even differences as small as 0.1 pH (4.2, 4.3, and 4.4 pH values were tested) can make a significant difference in the degradation rate of ''trans''-isohumulone into tricyclocohumol, with lower pH values leading to faster degradation. After storing beer in brown bottles at 28°C for 8 months, these degradation products were detected at high amounts. Tricyclohumol remains relatively stable, even in the presence of oxygen.
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