Fusel oil is produced by alcoholic fermentation which produces about 95% alcohol , and 5% oil of fusel oil (mixture of organic acids, alcohols superiors propanol , butanol , and alcohol amílico-, aldehydes and esters). It is found in a small proportion in wines and beer and in higher concentrations in spirits distilled in alembics. As the liquor matures, the fusel oil changes and imparts to the distillate its special aroma.
Summary
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- 1 Story
- 2 Composition
- 3 Natural state
- 4 Physical properties
- 1 Higher alcohols
- 2 Effects
- 3 levels
- 4 List of compounds
- 5 Analysis
- 5 Health effects
- 6 External links
- 7 Sources
History
Fusel alcohols, also sometimes called fusel oils, or potato oil in Europe, are higher-order alcohols (i.e. alcohols with more than two carbon atoms), formed by fermentation and present in cider , mead, beer , wine and spirits to varying degrees.
It is a mixture of volatile liquids, fat produced in small quantities during alcoholic fermentation. A typical fusel oil contains 60-70 percent amyl alcohol , small amounts of n-propyl and isobutyl alcohol, and traces of other components. Before industrial production of synthetic amyl alcohol fibers began in the 1920s , fusel oil was the only commercial source of these compounds, which are the main ingredients in lacquer solvents.
The fusel alcohols, apparently produced during the fermentation of amino acids . In industrial alcohol plants, fusel oil and ethyl alcohol are recovered from fermented liqueurs and separated by distillation. In the beverage industry, fusel oil is normally allowed to remain in finished products. The amount present in a test of 100 distilled spirits is typically between 0.5 and 2 grams per liter (0.07 and 0.3 ounces per gallon).
Composition
Part of the distillate from the fermentation liquids of sugars, cereal starches and fruit juices, formed by a mixture of alcohols including n-propyl, n-butyl and n-amyl.
- 1-propanol
- 2-propanol
- butanol various isomers)
- amyl alcohol
- furfural
Natural state
The compounds that will make up fusel oils are mainly composed of higher alcohols, especially amyl alcohol, esters, fatty acids and some specific aldehydes.
Higher alcohols, also known as fusel oils, are found in most fermented beverages. These are alcohols that have three (3) to six (6) carbon atoms per molecule. They are produced through the metabolization of nitrogenous compounds by yeasts. The term fusel oil comes from an old German word “fuseln”, which means “fudge” and was applied to the evil spirit as in distilled alcohol and bad tobacco.
Fusel oil strictly ends the remains of a distillation pot or batch, the compounds with low volatility. However, many of these compounds are obtained as part of the distillate, imparting their own unique flavor complexity, but can be very unpleasant if in excess.
Its harsh attributes require extended ripening time to integrate and smooth. Although it is not strictly oils they have an oily consistency. The non-volatility of an oily and higher alcohols nature resides in its high molecular weight and structure. While these alcohols, at high levels, have a high degree of toxicity, vomiting induced by them prevents deaths. However, they are a major contributor to hangovers. The higher the molecular weight of those related to alcohol, the worse the hangover.
Physical properties
It is the mixture of alcohols (largely amyl alcohols) and fatty acids, formed during the alcoholic fermentation of organic materials. After distillation of these fermentation products is imperfect it becomes an impurity in the distilled liquor. The oil fusel is used as a solvent in the manufacture of certain lacquers and enamels (dissolved nitrocellulose). It has a detrimental effect on the human system.
A clear yellowish liquid with an unpleasant odor and taste. It is a mixture of alcohols and fatty acids. It is a by-product of the production of fermented ethanol and is used as a solvent and in the manufacture of explosives and pure amyl alcohols.
Higher alcohols
They are present in wines and are formed in small quantities by the metabolism of yeast during alcoholic fermentation. Higher alcohols are produced either from sugars and amino acids (Erlich mechanism). Sugars and amino acids in a sequence of reactions are transformed into higher alcohols.
A higher alcohol can be related to its amino acid from which it is formed, some examples: leucine with 3-methylbutanol, isoleucine with 2-methylbutanol, Valine, with 2-methylpropanol, Threonine with propanol and phenylalanine with 2-phenylethanol.
The amount produced during fermentation depends on the genus, species and strain of yeast, the specific situation of nutrients ( nitrogen and amino acids) and the composition of the must and the temperature, aeration and pH during fermentation.
Effects
Higher alcohols can have an aromatic effect on wines and other higher alcohols that can be considered positive and others can be considered negative on the aromatic profile of the wine . However, due to the concentration found in wines and their high threshold, higher alcohols do not have many sensory effects on wine.
Higher alcohols are of great importance in wine distillation (grape alcohol or brandy), due to the fact that in higher alcohol distillates they are found in the grater concentration.
Levels
The total concentration range in wine is between 100-500 mg / L. Guymon and Heitz, 1952 (cited in Boulton et al 1996) reported the following concentration ranges for white wines (162-266 mg / L) and for red wines (140 – 417 mg / L), produced in California.
Isoamyl alcohol is the highest alcohol found in great wines (more than 50%) and its concentration has been reported in the range of 90 to 292 mg / L (Usseglio Tomasset-1975, cited in Boulton et al 1996).
Compound List
The four main higher alcohols are found in wines in order to the quantities produced are as follows:
- 3-methylbutanol (isoamyl alcohol): (CH 3) 2-CH-CH 2 -CH 2 -OH
- 2-methylbutanol (active amyl alcohol): CH 3-CH 2 -CH (CH 3 ) -CH 2 -OH
- 2-methylpropanol (isobutyl alcohol): (CH 3) 2 -CH-CH 2 -OH
- 1-propanol (n-propyl alcohol): CH 3-CH 2 -CH 2 -OH
Others that can be found, not limited below, are as follows:
- isopropanol: (CH 3) 2-CH-OH
- n-butanol: CH 3-CH 2 -CH 2 -CH 2 -OH
- n-amyl alcohol: CH 3-CH 2 -CH 2 -CH 2 -CH 2 -OH
- n-hexanol: CH 3-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -OH
- 2-phenylthanol: (C 6H 5 ) -CH 2 -CH 2 -OH
Analysis
Determination of higher alcohols is carried out with chromatographic analysis.
Health effects
There is a popular belief that fusel alcohol contributes to hangover symptoms. One study indicated that fusel alcohol does not have the most significant adverse health effects (headache, nausea, etc.) of ethanol, the main active ingredient in all alcoholic beverages. An animal model of hangover participated in the study, and its importance in humans is unclear.