Fusel alcohols

Yeast (qv) metabolize maltose and glucose sugars via the Embden-Meyerhof pathway to pymvate, and via acetaldehyde to ethanol. AH distiUers yeast strains can be expected to produce 6% (v/v) ethanol from a mash containing 11% (w/v) starch. Ethanol concentration up to 18% can be tolerated by some yeasts. Secondary products (congeners) arise during fermentation and are retained in the distiUation of whiskey. These include aldehydes, esters, and higher alcohols (fusel oHs). NaturaHy occurring lactic acid bacteria may simultaneously ferment within the mash and contribute to the whiskey flavor profile. 

Chemical Designationis - Synonyms Fementation amyl alcohol Fusel oil Isobutylcarbinol Isopentyl alcohol 3-Methyl-l-butanol Potato-spirit oil Chemical Formula (CH3)2CHCH2CH20H. Observable Characteristics - Physical(asshipped) Liquid Color Colorless Odor. Mild odor alcoholic, non-residual. 

Synonyms AI3-15288 C-07328 EINECS 204-663-5 FEMA No. 2057 Fermentation amyl alcohol Fusel oil IP3 l-Hydroxy-3-methylbutane Isoamylol Isobutyl carbinol Isopentanol Isopentyl alcohol Methyl-3-butan-l-ol 2-Methyl-4-butanol 2-Methylbutan-4-ol 3-Methylbutanol 3-Methylbutan-l-ol 3-Methyl-l-butanol NSC 1029 Primary isoamyl alcohol Primary isobutyl alcohol UN 1105. 

ISOAMYL ALCOHOL Fermentation amyl alcohol, Fusel oil, Isopentyl alcohol, 3-MethyH-butanol Combustible Liquid 1 2 0... 

Tills is generally associated with the familiar alcoholic fermentation in which theoretically 100 parts of glucose are converted to 51.1 parts of ethyl alcohol (ethanol). 48.9 parts of carbon dioxide (CO/i. and heat. In addition, however, the anaerobic reaction also yields minor byproducts in small amounts—mainly glycerol, succinic acid, higher alcohols (fusel oil), 2,3-butanediol, and traces of acetaldehyde, acetic acid, and lactic acid. Fusel oil is a mixture of alcohols, including -propyl, -butyl, isobutyl, amyl, and isoamyl alcohols. 

Amyl Alcohol (Pentanols, Pentyl Alcohols, Fusel Oil, and Potato Spirit) Molecular formula C5H11OH... 

Synonyms and trade names pentanols, pentyl alcohols, fusel oil, and potato spirit... 

When the mash ferments sugar it forms alcohol and also carbon dioxide which bubbles up from the mash. As well as alcohol, fusel oil is formed. This is the cover name for the small amounts of impurities made by the yeast. Ideally it would be best if the yeast only formed alcohol but this ideal has not been achieved yet. Every year new types of yeast are developed that in principle ferment faster and above all, cleaner. Fusels are not useful but are formed in such small amounts that they are not harmful, but we want to get rid of them anyway. Both taste and aroma are ruined by fusels. The reason the distillate smells a bit is because the fusels are apparent when there is only alcohol, water and by-products. 

Amyl alcohol, commercial EINECS 232-395-2 FEMA No, 2497 Fusel oil Fusel oil, refined Fusel oil, refined (mixed amyl alcohols) Fusel oil, sugar beet Fusel oil Fuselol Hulle de fusel Isoamyl fusel oil UNI 201, 232-395-2... 

As the result of the fermentation there is obtained a mixture which contains water, alcohol, fusel oil, acids, yeast cells, and other substances. The alcohol, which is present to the extent of from 10 to 13 per cent, is separated by distillation. Very efficient rectifying apparatus is used in distilling the dilute solution of alcohol. After two distillations alcohol containing but 4 per cent of water is obtained. A mixture of alcohol and water which contains 96 per cent of alcohol by weight cannot be separated into its constituents by distillation, as a mixture of this composition has a constant boiling point below that of pure alcohol. Toward the end of the distillation there is obtained what is called fusel oil, which consists of two isomeric amyl alcohols, CsHnOH, together with small quantities of other alcohols. 

Another t5q)ical example is removal of higher-boiling alcohols ("fusel oil ) from ethanol-water columns. Unless removed, they will concentrate in the column, and upon reaching their solubility limit, form a second phase and cause cyclic flooding (362) as described earlier. Fusel oil is commonly removed by a similar scheme to Fig. 13.5, except that the side stream is usually cooled prior to phase... 

Alcohol solutions, 3.3 Denatured alcohol, 3 Fermentation amyl alcohol Fusel oil,... 

Formaldehyde ethyl cyclododecyl acetal Formaldehyde methyl cyclododecyl acetal Furfuryl alcohol Fusel oil refined Geranyl acetoacetate... 

The yeast oxo-acid pool is also the source of substrates for the synthesis of aldehydes and fusel alcohols. Fusel alcohols are so named because they... 

The aroma and taste of alcoholic beverages are critical to their acceptance by consumers, and the primary determinants of aroma and taste are volatile compounds. For mezcal, some of the volatile compoxmds are specified by Mexican laws (SCFI 1997), including methanol, higher alcohols (fusel alcohols), and the compounds that influence volatile acids like acetic acid. These specifications are shown in table 1. 

Alcoholic Higher alcohol/fusel picy/citrus/flotal... 

Higher alcohol/fusel Spicy/citrus/floral... 

Fig. 4-1. Generalized pathway for formation of higher alcohols ( fusel oils ) from amino acid and alphorketo acid precursors.

After 40-60 hours, fermentation is complete, and the product is distilled to remove the alcohol from solid matter. The distillate is fractionated by means of an efficient column. A small amount of acetaldehyde (bp 21 °C) distills first and is followed by 95% alcohol. Fusel oil is contained in the higher-boiling fractions. The fusel oil consists of a mixture of higher alcohols, chiefly 1-propanol, 2-methyl-l-propanol, 3-methyl-l-butanol, and 2-methyl-l-butanol. The exact composition of fusel oil varies considerably it particularly depends on the type of raw material that is fermented. These higher alcohols are not formed by fermentation of glucose. They arise from certain amino acids derived from the proteins present in the raw material and the yeast. These fusel oils cause the headaches associated with drinking alcoholic beverages. 

Chemical Designations — Synonyms Fermentation amyl alcohol Fusel oil Iso-butylcarbinol Isopentyl alcohol 3-Methyl-l-butanol Potato-spirit oil Chemical Formula (CH3)2CHCH2CH20H. Observable Characteristics — Physical State (as shipped) Liquid Color Colorless Odor Mild odor alcoholic, non-residual. Physical and Chemical Properties — Physical State at 15"C and 1 atm. Liquid Molecular Weight 88.15 Boiling Point at 1 atm. 270, 132, 405 Freezing Point Not pertinent Critical Temperature 585, 307, 580 Critical Pressure Not pertinent Specific Gravity 0.81 at 20"C (liquid) Vapor (Gas) Specific Gravity Not pertinent Ratio of Specific Heats of Vapor (Gas) (est.) 1.062 Latent Heat of Vaporization 215.6, 119.8, 5.016 Heat of Combustion -16,200, -9,000, -376.8 ... 

ISOAMYL ALCOHOL (CH,),CHCH,CH,OH Methyl-1 butaiiol. Isobutykarblnol, Isopentyl alcohol, Fermentation amyl alcohol, Fusel oil Strong oddizers 109 1.2 (2im 9ai2-F)... 

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