Geosmin

A good example of this is geosmin, for which a typical sensitivity for the human nose is below 10 parts per trillion (10 parts in 10¹⁸ v/v) (ppt).

A. versicolor may be one of the major producers of the moldy smelling component, geosmin, in buildings (Bjurman and Kristensson 1992).

Beetroots: The flavor is decisively characterized by the earthy note of geosmin