Geosmin is responsible for the earthy taste of beets and a contributor to the strong scent that occurs in the air when rain falls after a dry spell of weather (petrichor) or when soil is disturbed.
The human nose is extremely sensitive to geosmin and is able to detect it at concentrations as low as 5 parts per trillion.

komt van een leuke FB pagina;
https://www.facebook.com/IFeakingLoveScience