Higher alcohols (also called Fusel oil) are alcohols that have more than 2 carbons (Ethanol has two carbons CH3-CH2-OH) and thus have higher molecular weight and higher boiling point. … Higher alcohols are present in wines and are formed in small amounts by yeast metabolism during the alcoholic fermentation process.
https://waterhouse.ucdavis.edu/whats-in-wine/higher-alcohols