AbstractFusel oils from Australian grape wines (Vine sp.Vitis vinifera) have been found to consist substantially of ethanol,n‐propanol, isobutanol (2‐methyl‐1‐propanol), isoamyl alcohol (3‐methyl‐1‐butanol) and active amyl alcohol (2‐methyl‐1‐butanol). In addition there are present large numbers of aliphatic esters, believed to be of considerable importance to grape brandy and spirit flavour and quality. The quantities and occurrence of these esters have been found to follow a systematic pattern. The major esterified alcohols are related to the free alcohols present and the major esterified acids occur as a series of acids of even carbon number with a maximum concentration at then‐decanoic acid. These relationships provide a basis for calculating the approximate ester com