Wine Analysis Home
Fusel Oil (Higher Alcohols)
- The higher alcohols, also referred to as fusel oils, are found in most fermented beverages.
These are the alcohols that have three (3) to six (6) carbon atoms per molecule (see diagram).
- They are produced through the metabolisation of nitrogenous compounds by yeasts.
- The term fusel oil comes from an old German word "fuseln", which means "to bungle" and was applied to bad spirit as in distilled alcohol and also bad tobacco.
The term fusel oil is strictly the remains of a pot or batch distillation, the compounds with low volatility.
However, many off these compounds are collected as part of the distillate, imparting their own unique flavour complexity, but can be quite obnoxious if in excess.
Their harsh attributes require extended maturation time to integrate and mellow.
The compounds that go to make up fusel oils predominantly consists of higher alcohols, especially amyl alcohol, esters, fatty acids and some specific aldehydes.
While not strictly oils have an oily consistency.
The non-volatility and oily nature of higher alcohols lies in their high molecular weight and structure.
- While these alcohols, at high levels, have a high toxicity, the induced vomiting they trigger prevent fatalities.
They are however a major contributor to hangovers. The higher the molecular weight of the alcohol involved, the worse the hangover.
- The higher alcohols include -
| Alcohol | % w/w per
higher alcohol. | Number of
carbon Atoms |
isoamyl alc.
(see diagram) | 54 | 5 |
| isobutyl alc. | 18.3 | 4 |
| active-amyl alc. | 9.6 | 5 |
| butyl alc. | 4.9 | 4 |
| propyl alc.. | 4.1 | 3 |
| hexanol | 1.5 | 6 |