Fusel oil

Fusel oil is a mixture of higher alcohols produced during fermentation, consisting mainly of isobutyl alcohol and isoamyl alcohol. These alcohols are generally one of the elements that influence the aroma and flavor of sake. At low concentrations, fusel oil has a distinctive aroma and helps enrich the overall taste, but at high concentrations it can give off an unpleasant smell and may adversely affect quality. For this reason, managing fusel oil is important during the brewing process.