Term describing odors deriving from varietal yeasts carried on grapeskins, molds etc. Includes both desirable and undesirable characteristics. Examples would be the presence of "brett", (brettanomeyces), a strain of yeast that produces "gamey/smokey" odors that are considered to add to the character of the wine when barely detectable. Considered a flaw when presence is pronounced. Another, similar example is the "dekkera" wild yeast strain which gives a "fresh dirt/cement-y" flavor component.