A top priority for winemakers is to produce high quality wine that does not contain any faults or defects. A wine fault is an unpleasant organoleptic characteristic including look, smell, or taste. Wine faults can come from a chemical or a microbial origin and some off-odors can be the result of multiple faults. It can be challenging to identify some of the common defects, as wine faults are not always straightforward. Factors such as the type or style of wine, the stage of production, the wine age, and the person smelling or tasting all contribute to the perception of a wine fault.