Definitions

1. noun

A mixture of alcohols produced in the fermentation of grain, especially those that are higher boiling point than the main spirit being produced.

“The fusel oil from the fermentation process had a strong, unpleasant smell.”

2. noun

A type of secondary fermentation that can occur in beer brewing, producing unwanted compounds.

“The brewer was concerned about the fusel in the beer, which gave it an off flavor.”