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 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 acetate ...

) 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 ...

of alcoholic fermentation. 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 **Ge ...

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 h ...

". 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, gastroenteritis ...

response" in the Asian house shrew. 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 with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

suppressed subjects' subsequent taste aversion 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 c ...

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 Ph ...

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 ca ...

(especially bourbon), incompletely rectified vodka (e.g. Siwucha) and traditional

ale Ale is a type of beer brewed using a 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 typically has a bittering agent to bala ...

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 impuriti ...

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 "storag ...

s, the presence of alcohols other than ethanol is considered a fault. The compounds involved are chiefly the following: * isoamyl alcohol (isopentanol) * 2-methyl-1-butanol - sometimes called "active"

* isobutyl alcohol - 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 fer ...

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 sim ...

(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 NA ...

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-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- ...

(''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 additiona ...

* 2-phenylethanol

Distillation

During

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

, 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 reaction ...

. On the other hand,

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

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 p ...

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