13,703
edits
Changes
Hops
,→Chemistry and Characteristics
| 4'-hydroxyallohumulinones || Humulinones || ? || Not reported; might contribute to bitterness of beers with high amounts of aged hops. || Believed to be derived from the oxidation of humulinone in hops. They are more stable than humulinone over time and are thus thought to be useful indicators of the degree of oxidation in hops.
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| 4'-Hydroxyallo-cis-humulinones and cis-oxyhumulinic acids || 4'-hydroxyallohumulinones || Y || Contributes to bitterness quality || These are formed during boiling where 4'-hydroxyallohumulinones are isomerized into 4'-Hydroxyallo-cis-humulinones for the first 60 minutes of boiling, and then the 4'-Hydroxyallo-cis-humulinones are slowly degraded into cis-oxyhumulinic acids after 60 minutes of boiling. After 120 minutes of boiling, 40-50% of the 4'-hydroxyallohumulinones is transformed into 4'-Hydroxyallo-cis-humulinones and cis-oxyhumulinic acids. These are thought to effect the bitterness quality of beer, and as hard resins they could help improve head retention <ref>[https://www.researchgate.net/publication/286063120_Contributions_of_hop_hard_resins_to_beer_quality Almaguer, Cynthia & Gastl, Martina & Arendt, Elke & Becker, Th. (2012). Contributions of hop hard resins to beer quality. BrewingScience. 65. 118-129..]</ref>.
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