Editing Hops (section)

==Chemical composition==
In addition to water, cellulose, and various proteins, the chemical composition of hops consists of compounds important for imparting character to beer.<ref name=schon/><ref name="Verzele 32–48">{{Cite journal |last=M. Verzele |date=2 January 1986 |title=100 Years of Hop Chemistry and Its Relevance to Brewing |journal=Journal of the Institute of Brewing |volume=92 |issue=1 |pages=32–48 |doi=10.1002/j.2050-0416.1986.tb04372.x |issn=2050-0416 |doi-access=free}}</ref>

=== Alpha acids ===
[[File:Reaction-degradation-humulone.png|thumb|upright=1.5|Isomerization scheme of humulone]]

Probably the most important chemical compound within hops are the alpha acids or [[humulone]]s. During wort boiling, the humulones are thermally isomerized into iso-alpha acids or [[Isohumulone|''isohumulones'']], which are responsible for the bitter taste of beer.<ref name="De Keukeleire 108–112">{{Cite journal |last=Denis De Keukeleire |year=2000 |title=Fundamentals of beer and hop chemistry |journal=Química Nova |volume=23 |issue=1 |pages=108–112 |doi=10.1590/S0100-40422000000100019 |issn=0100-4042 |doi-access=free}}</ref>

=== Beta acids ===
[[File:Lupulone.svg|thumb|upright|Structure of [[lupulone]] (beta acid)]]

Hops contain beta acids or [[lupulone]]s. These are desirable for their aroma contributions to beer.<ref>{{Cite book |last1=Ortega-Heras |first1=M. |title=Encyclopedia of Food Sciences and Nutrition |last2=González-Sanjosé |first2=M.L. |date=2003 |publisher=Academic Press |isbn=9780122270550 |editor-last=Benjamin |editor-first=Caballero |edition=Second |pages=429–434 |chapter=BEERS {{!}} Wort Production |doi=10.1016/B0-12-227055-X/00087-0}}</ref>

=== Essential oils ===
The main components of hops essential oils are [[terpene]] [[hydrocarbon]]s consisting of [[myrcene]], [[humulene]] and [[caryophyllene]].<ref name="Verzele 32–48" /> Myrcene is responsible for the pungent smell of fresh hops. Humulene and its oxidative reaction products may give beer its prominent hop aroma. Together, myrcene, humulene, and caryophyllene represent 80 to 90% of the total hops essential oil.<ref name="Verzele 32–48" /> 

=== Flavonoids ===
[[File:8-Prenylnaringenin.svg|thumb|upright|Chemical structure of 8-prenylnaringenin]]

[[Xanthohumol]] is the principal [[flavonoid]] in hops. The other well-studied [[prenylflavonoid]]s are [[8-Prenylnaringenin]] and [[isoxanthohumol]]. Xanthohumol is under [[basic research]] for its potential properties, while 8-prenylnaringenin is a potent [[phytoestrogen]].<ref>{{Cite journal |last1=Stevens |first1=Jan F |last2=Page |first2=Jonathan E |date=1 May 2004 |title=Xanthohumol and related prenylflavonoids from hops and beer: to your good health! |journal=Phytochemistry |volume=65 |issue=10 |pages=1317–1330 |doi=10.1016/j.phytochem.2004.04.025 |pmid=15231405|bibcode=2004PChem..65.1317S }}</ref><ref>{{Cite journal |last1=Milligan |first1=S |last2=Kalita |first2=J |last3=Pocock |first3=V |last4=Heyerick |first4=A |last5=Cooman |first5=L De |last6=Rong |first6=H |last7=Keukeleire |first7=D De |year=2002 |title=Oestrogenic activity of the hop phyto-oestrogen, 8-prenylnaringenin |url=https://www.researchgate.net/publication/11494867 |journal=Reproduction |volume=123 |issue=2 |pages=235–242 |doi=10.1530/rep.0.1230235 |pmid=11866690 |doi-access=free}}</ref>