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 An amyl alcohol is any of eight alcohols with the formula C5H12O. A mixture of pentyl, amyl alcohols (also called amyl alcohol) can be obtained from fusel alcohol. Amyl alcohol is used as a solvent and in esterification, by which is produced amyl a ...

) produced as a

by-product A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be consid ...

alcoholic fermentation Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products. Because yeasts perform this ...

. The word ''Fusel'' is

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

for "bad

liquor Liquor (or a spirit) is an alcoholic drink produced by distillation of grains, fruits, vegetables, or sugar, that have already gone through alcoholic fermentation. Other terms for liquor include: spirit drink, distilled beverage or hard ...

". Whether fusel alcohol contributes to

hangover A hangover is the experience of various unpleasant physiological and psychological effects usually following the consumption of alcohol, such as wine, beer, and liquor. Hangovers can last for several hours or for more than 24 hours. Typical sympto ...

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 Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteri ...

response" in the

Asian house shrew The Asian house shrew (''Suncus murinus'') is a shrew species native to South and Southeast Asia that has been listed as Least Concern on the IUCN Red List since 2008 because of its large population and wide distribution. It has been introduced i ...

. Additionally, consumption of fusel oils with

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

suppressed subjects' subsequent

taste aversion Conditioned taste aversion occurs when an animal acquires an aversion to the taste of a food that was paired with aversive stimuli. The Garcia effect is that the aversion develops more strongly for stimuli that cause nausea than other stimuli. Th ...

to alcohol, which suggested subjects' hangover symptoms were lessened, according to the journal.

Usage

Fusel oil and fusel-oil acetates are used in the

lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be ca ...

industry as high boiling point

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

Compounds

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 Rum is a liquor made by fermenting and then distilling sugarcane molasses or sugarcane juice. The distillate, a clear liquid, is usually aged in oak barrels. Rum is produced in nearly every sugar-producing region of the world, such as the Phili ...

whisky Whisky or whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Various grains (which may be malted) are used for different varieties, including barley, corn, rye, and wheat. Whisky is typically aged in wooden c ...

(especially

bourbon Bourbon may refer to: Food and drink * Bourbon whiskey, an American whiskey made using a corn-based mash * Bourbon barrel aged beer, a type of beer aged in bourbon barrels * Bourbon biscuit, a chocolate sandwich biscuit * A beer produced by Bras ...

), incompletely rectified vodka (e.g.

Siwucha Siwucha () is an incompletely rectified vodka ( raw vodka) from Poland. The name derives from the ''siwy'' (ash grey) color of the liquid due to Tyndall effect of the colloid emulsion of residual fusel oil. History Siwucha is one of the generi ...

) and traditional

ale Ale is a Type of beer, type of beer brewed using a Warm fermentation, warm fermentation method, resulting in a sweet, full-bodied and fruity taste. Historically, the term referred to a drink brewed without hops. As with most beers, ale typicall ...

s and

cider Cider ( ) is an alcoholic beverage made from the fermented juice of apples. Cider is widely available in the United Kingdom (particularly in the West Country) and the Republic of Ireland. The UK has the world's highest per capita consumption, ...

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 Korn (stylized as KoЯn, or occasionally KoRn) is an American nu metal band from Bakersfield, California, formed in 1993. The band is notable for pioneering the nu metal genre and bringing it into the mainstream. Originally formed in 1993 ...

vodka Vodka ( pl, wódka , russian: водка , sv, vodka ) is a clear distilled alcoholic beverage. Different varieties originated in Poland, Russia, and Sweden. Vodka is composed mainly of water and ethanol but sometimes with traces of impuritie ...

and

lager Lager () is beer which has been brewed and conditioned at low temperature. Lagers can be pale, amber, or dark. Pale lager is the most widely consumed and commercially available style of beer. The term "lager" comes from the German for "storage" ...

s, the presence of alcohols other than ethanol is considered a fault. The compounds involved are chiefly the following: *

isoamyl alcohol Isoamyl alcohol is a colorless liquid with the formula , specifically (H3C–)2CH–CH2–CH2–OH. It is one of several isomers of amyl alcohol (pentanol). It is also known as isopentyl alcohol, isopentanol, or (in the IUPAC recommended nomencla ...

(isopentanol) *

2-methyl-1-butanol 2-Methyl-1-butanol (IUPAC name, also called active amyl alcohol) is an organic compound with the formula CH3CH2CH(CH3)CH2OH. It is one of several isomers of amyl alcohol. A colorless liquid, it occurs naturally in trace amounts and has attracted ...

- sometimes called "active"

isobutyl alcohol Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH3)2CHCH2OH (sometimes represented as ''i''-BuOH). This colorless, flammable liquid with a characteristic smell is mainly used as a solvent either dire ...

- one of the least toxic of the butanols. *

1-propanol Propan-1-ol (also propanol, n-propyl alcohol) is a primary alcohol with the formula and sometimes represented as PrOH or ''n''-PrOH. It is a colorless liquid and an isomer of 2-propanol. It is formed naturally in small amounts during many ferme ...

Other higher alcohols that can be produced during fermentation include: *

isopropanol Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable organic compound with a pungent alcoholic odor. As an isopropyl group linked to a hydroxyl group (chemical formula ) it is the simple ...

(isopropyl alcohol), oxidized to form acetone by

alcohol dehydrogenase Alcohol dehydrogenases (ADH) () are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to N ...

in the liver, leading to

ketosis Ketosis is a metabolic state characterized by elevated levels of ketone bodies in the blood or urine. Physiological ketosis is a normal response to low glucose availability, such as low-carbohydrate diets or fasting, that provides an additional ...

when ingested in large quantities. *

1-butanol 1-Butanol, also known as butan-1-ol or ''n''-butanol, is a primary alcohol with the chemical formula C4H9OH and a linear structure. Isomers of 1-butanol are isobutanol, butan-2-ol and ''tert''-butanol. The unmodified term butanol usually refers t ...

1-pentanol 1-Pentanol, (or ''n''-pentanol, pentan-1-ol), is an alcohol with five carbon atoms and the molecular formula C5H11OH.CRC Handbook of Chemistry and Physics 65Th Ed. 1-Pentanol is a colourless liquid with a distinctive aroma. It is the straight-ch ...

(''n''-amyl alcohol) *

1-hexanol 1-Hexanol (IUPAC name hexan-1-ol) is an organic alcohol with a six-carbon chain and a condensed structural formula of CH3(CH2)5OH. This colorless liquid is slightly soluble in water, but miscible with diethyl ether and ethanol. Two additional st ...

2-phenylethanol Phenethyl alcohol, or 2-phenylethanol, is the organic compound that consists of a phenethyl group (C6H5CH2CH2) attached to OH. It is a colourless liquid that is slightly soluble in water (2 ml/100 ml H2O), but miscible with most organic solvents. ...

Distillation

During

distillation Distillation, or classical distillation, is the process of separation process, separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distilla ...

, 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 Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to reactions ...

. On the other hand,

freeze distillation Fractional freezing is a process used in process engineering and chemistry to Separation process, separate substances with different melting points. It can be done by partial melting of a solid, for example in zone melting, zone refining of sili ...

does not remove fusel alcohols. Fusel alcohols are formed when

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

occurs * at higher temperatures * at lower pH * when yeast activity is limited by low nitrogen content

References

External links

* {{Alcohol and health Alcohols Distillation Flavors Alcohol chemistry

Usage

Compounds

Distillation

See also

References

External links