Isoamyl alcohol

Isoamyl alcohol (also known as isopentyl alcohol) is a colorless liquid with the formula (CH₃)₂CHCH₂CH₂OH. It is one of several isomers of amyl alcohol. It is an ingredient in the production of banana oil, an ester found in nature and also produced as a flavouring in industry. It is a common fusel alcohol, produced as a major by-product of ethanol fermentation. It is also an ingredient of Kovac's reagent, used for the bacterial diagnostic indole test.

It is also used as an antifoaming agent in the chloroform:isomyl alcohol reagent.

Isoamyl alcohol is used in a phenol–chloroform extraction mixed with the chloroform to further inhibit RNase activity and prevent solubility of RNAs with long tracts of poly-adenine.

It is one of the components of the aroma of Tuber melanosporum, the black truffle. It has been identified as a chemical in the pheromone used by hornets to attract other members of the hive to attack.