Acetaldehyde
/as-et-AL-duh-hide/A chemical compound formed during fermentation and oxidation.
Full Definition
Acetaldehyde is an intermediate compound in fermentation, normally converted to ethanol by yeast. When present in excess due to oxidation or incomplete fermentation, it imparts bruised apple, sherry-like, or nutty aromas. It's intentionally cultivated in Fino and Manzanilla sherries but considered a fault in most table wines.