Editing Fusel alcohol

{{also|Comparison of psychoactive alcohols in alcoholic drinks}}
{{Short description|Alcoholic fermentation byproduct}}

'''Fusel alcohols''' or '''fuselol''', also sometimes called '''fusel oils''' in Europe, are mixtures of several '''higher alcohols''' (those with more than two carbons, chiefly [[amyl alcohol]]) produced as a [[by-product]] of [[alcoholic fermentation]].<ref>{{Cite web | url=http://oxforddictionaries.com/definition/english/fusel%2Boil | title=Fusel oil | website=Oxford Dictionaries | access-date=2013-01-21 | archive-date=2013-01-26 | archive-url=https://web.archive.org/web/20130126224105/http://oxforddictionaries.com/definition/english/fusel%2Boil | url-status=dead }}<br />- {{cite web |last1=Blazquez |first1=Rodrigo |title=Higher Alcohols |url=https://waterhouse.ucdavis.edu/whats-in-wine/higher-alcohols |website=Waterhouse Lab |date=March 2019 |publisher=UC Davis |access-date=22 September 2020 }}</ref> The word ''Fusel'' {{IPA|de|ˈfuːzl̩|}} is [[German language|German]] for "bad [[liquor]]".<ref>{{Cite journal | last1 = Hazelwood | first1 = Lucie A. | last2 = Daran | first2 = Jean-Marc | last3 = van Maris | first3 = Antonius J. A. | last4 = Pronk | first4 = Jack T. | last5 = Dickinson | first5 = J. Richard | title = The Ehrlich pathway for fusel alcohol production: a century of research on ''Saccharomyces cerevisiae'' metabolism | journal = Appl. Environ. Microbiol. | volume = 74 | issue = 8 | pages = 2259–66 | year = 2008 | pmid = 18281432 | pmc = 2293160 | doi = 10.1128/AEM.02625-07 | bibcode = 2008ApEnM..74.2259H }}</ref>

Whether fusel alcohol contributes to [[hangover]] symptoms is a matter of scientific debate. A Japanese study in 2003 concluded that "the fusel oil in whisky had no effect on the ethanol-induced [[emetic]] response" in the [[Asian house shrew]]. Additionally, consumption of fusel oils with [[ethanol]] suppressed subjects' subsequent [[conditioned taste aversion|taste aversion]] to alcohol, which suggested subjects' hangover symptoms were lessened, according to the journal.<ref>{{cite journal|vauthors=Hori H, Fujii W, Hatanaka Y, Suwa Y |date=27 August 2003|title= Effects of fusel oil on animal hangover models.|journal= Alcohol Clin Exp Res|pmid=12960505|doi=10.1097/01.ALC.0000078828.49740.48|volume=27|issue=8 Suppl|pages=37S–41S|doi-access=free}}</ref>

== Usage ==
Fusel oil and fusel-oil acetates are used in the [[lacquer]] industry as high boiling point [[solvent]]s.<ref>{{cite journal |doi=10.1021/ie50492a004 |title=Amyl Compounds from Pentane|journal=[[Industrial & Engineering Chemistry]] |volume=42 |issue=12 |pages=2388–2401 |year=1950 |last1=Kenyon |first1=Richard L. |last2=Inskeep |first2=Gordon C. |last3=Gillette |first3=Leslie |last4=Price |first4=J. Frank}}</ref>

== Compounds ==
{{Further|Congener (alcohol)}}

Excessive concentrations of some alcohols other than ethanol may cause off-flavors, sometimes described as "spicy", "hot", or "solvent-like". Some beverages, such as [[rum]], [[whisky]] (especially [[Bourbon whiskey|bourbon]]), incompletely [[Rectified spirit|rectified]] vodka (e.g. [[Siwucha vodka|Siwucha]]) and traditional [[ale]]s and [[cider]]s, are expected to have relatively high concentrations of non-hazardous alcohols as part of their flavor profile. However, in other beverages, such as [[Korn (liquor)|Korn]], [[vodka]] and [[lager]]s, the presence of alcohols other than ethanol is considered a [[Wine fault|fault]].<ref>Aroma of Beer, Wine and Distilled Alcoholic Beverages</ref>{{Failed verification|date=August 2023}}

The compounds involved are chiefly the following:<ref>{{cite book|title=MERCK INDEX|edition=10th|year=1983}}</ref>

* [[isoamyl alcohol]] (isopentanol)
* [[2-methyl-1-butanol]] - sometimes called "active" [[amyl alcohol]]
* [[isobutyl alcohol]] - one of the least toxic of the butanols.
* [[1-propanol]]

Other higher alcohols that can be produced during fermentation include:

* [[isopropanol]] (isopropyl alcohol), oxidized to form acetone by [[alcohol dehydrogenase]] in the liver, leading to [[ketosis]] when ingested in large quantities.
* [[1-butanol]]
* [[1-pentanol]] (''n''-amyl alcohol)
* [[1-hexanol]]
* [[2-phenylethanol]]
* [[tyrosol]]
* [[tryptophol]]
* [[methionol]]

==Distillation==
During [[distillation]], fusel alcohols are concentrated in the feints or "tails" at the end of the distillation run. They have an oily consistency, which is noticeable to the distiller, hence the other name "fusel oil". If desired, these heavier alcohols can be almost completely separated in a [[reflux still]]. On the other hand, [[freeze distillation]] does not remove fusel alcohols.{{Citation needed|date=June 2011}}

Fusel alcohols can be reduced during [[Fermentation (biochemistry)|fermentation]] by lowering the fermenter's temperature or increasing the oxygen content.<ref>{{cite web | url=https://escarpmentlabs.com/en-us/blogs/resources/avoid-the-dreaded-cheap-booze-flavour-5-strategies-for-fusel-alcohols | title=Avoid the Dreaded Cheap Booze Flavour: 5 Strategies for Fusel Alcohols }}</ref>

== See also ==
* [[Alcohol (drug)]]
* [[Reinheitsgebot|Beer purity law (1516)]]
* [[Biofuel]]
* [[Cellulosic ethanol]]
* [[Moonshine]]
* [[Beer in South Africa#History|Sorghum beer]]
* [[Wine chemistry]]

==References==
{{reflist|30em}}

==External links==
*{{Cite EB1911|wstitle=Fusel Oil |short=x}}

{{Alcohol and health}}

[[Category:Alcohols]]
[[Category:Distillation]]
[[Category:Flavors]]
[[Category:Alcohol chemistry]]