Answer: fusel

AnswerCrossword Clue
FUSELBy-product of bad liquor.
FUSELAcrid liquid in raw liquor.
FUSELOily, acrid liquid.
FUSELAcrid oily liquid.
FUSEL... oil (a source of alcohol)
fuselan acrid oily liquid occurring in insufficiently distilled alcoholic liquors, consisting chiefly of amyl alcohol, and used especially as a source of alcohols and as a solvent
fuselan oily liquid