hop
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Hop is a climbing plant in the hemp family whose cones (hop strobiles) add bitterness and aroma to beer. Bitter-acid content, including alpha and beta acids, differs substantially by cultivar.
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Reading the bitterness
Hops are climbing plants in the hemp family; their enlarged female inflorescences, called cones or strobiles, are used to add bitterness and aroma to beer. The amounts of the two bitter-acid classes, alpha and beta acids, vary substantially by cultivar, so bitterness differs widely even within hops. An EU protected designation of origin specification provides an example of chemical standards for the covered cultivars: alpha-acid content of 2.5–5.5% and a beta-to-alpha acid ratio of 0.60–0.80.
These standards describe only certain cultivated lines grown in the Czech Žatec region, such as Lučan (1941) and Blato (1952), eligible for the designation 'Žatecký chmel' (Žatec hops). The protected alpha-acid range of 2.5–5.5% is relatively mild compared with high-alpha-acid cultivars. The scheme thus protects a regional identity characterized by a particular mild bitterness profile, rather than bitterness strength itself. This conclusion is limited to the content of the 2006 registration notice (application publication).
Other hop lines have been bred expressly to increase bitterness-related acid content. The USDA 21267M line (registration number GP-37), released by USDA-ARS on December 6, 2011, is a male plant from a cross between the 1973 cultivar 'Comet' and the USDA-ARS 21110M line. It was recorded as a line with high alpha-acid content alongside yield and xanthohumol composition. The alpha-acid percentage has been checked only at the abstract level; no numerical value has been confirmed.
Within hops, a system protecting a mild bitterness profile under a regional name coexists with a breeding objective of increasing bitter acids themselves. The full EU registration regulation and detailed numerical values in the breeding paper have not yet been checked; this account is limited to the notice and abstract.
A study comparing cones from 15 international cultivars grown under the same conditions in an experimental field in central Italy’s Marche region found that total alpha acids (on a dry-matter basis), precursors of bitter-tasting compounds, varied substantially by cultivar. The highest level was in Nugget (10.61% ± 0.20%), followed by Chinook (7.98% ± 0.37%) and Yeoman (7.81% ± 0.03%); the lowest was in Willamette (0.65% ± 0.03%). The between-cultivar differences were statistically significant.
Sources for this overview
Checked for this overview: Confirmed chemical specifications including alpha acids at 2.5–5.5%. / Confirmed the covered lines, region, and mild bitterness range.
Registration of High Alpha-Acid Male Hop Germplasm USDA 21267M
Checked for this overview: Confirmed the breeding registration history of the high-alpha-acid line. / Confirmed the limitation that the specific alpha-acid percentage is undetermined.
Checked for this overview: Comparison of total alpha-acid content (a precursor) in 15 cultivars under the same conditions.
Other names: Humulus lupulus (la)
Structured claims — open a section to read each claim's confidence, evidence and limits
Composition and content (1)
Scope: Layer: food (cones, dry-matter basis, mean ± standard deviation, Tukey test p<0.05). Direct measurements comparing 15 cultivars in the same field under the same conditions (Table 2).
Note: Full text checked (full_text_checked). In addition to existing hop claims (TAS2R responses, hard resins, and high-alpha-acid breeding-line registration), this adds a cross-cultivar comparison under the same conditions.
Show data
organism-humulus-lupulus —has_composition→ "Cones from 15 international cultivars grown under the same conditions (Marche, central Italy) differed substantially in total alpha-acid content (dry-matter basis), a precursor of bitter-tasting compounds. Nugget was highest at 10.61% (±0.20%), followed by Chinook at 7.98% (±0.37%) and Yeoman at 7.81% (±0.03%); Willamette was lowest at 0.65% (±0.03%). The between-cultivar differences were statistically significant."Safety and regulation (2)
Scope: The Zatec region of the Czech Republic (the districts of Louny, Rakovník, Chomutov, Kladno, Plzeň-sever [northern Plzeň], and Rokycany)
Note: A factual record based on the registration procedure's notice (the 2006 official journal). This is not a claim guaranteeing the measured values of any individual lot. An alpha-acid content of 2.5-5.5% falls on the low side compared with high-alpha varieties, so the institution protecting bitterness here protects a specific, mild bitterness profile, not the strength of bitterness.
Show data
organism-humulus-lupulus —is_registered_as_eu_geographical_indication→ "The subject of an EU Protected Designation of Origin (PDO) notice as 'Zatecky chmel' (Saaz hops). The eligible clones are limited to Lučan (1941), Blato (1952), Osvaldův klon 31/72/114 (1952), Siřem (1969), Zlatan (1976), Podlešák (1989), and Blšanka (1993), and the specification includes chemical standards of alpha-acid content 2.5-5.5% and a beta-acid/alpha-acid ratio of 0.60-0.80."Scope: Humulus lupulus (USDA-ARS breeding line, male plant).
Note: The abstract says only that the line was registered for its 'high alpha-acid content'; a specific alpha-acid percentage has not been verified in the original text. Several secondary sources report 53.2% v/v alpha acids and 18.1% v/v beta acids, but these values are excluded from the claim because the publisher site returned 403 and the full text could not be accessed.
Show data
organism-humulus-lupulus —has_cultivar→ "The USDA 21267M line (Reg. No. GP-37, PI 559093) was registered and released with the objective of increasing alpha-acid content, an indicator of bittering potential. It derives from a 1973 cross of 'Comet' with the USDA-ARS 21110M line and was released on December 6, 2011."