geosmin, a compound with a strong earthy or muddy aroma that is a by-product of soil bacteria and is usually associated with wine faults. Found in red and white wines made with rotten grapes, it is also present in some wines with cork taint. The same aroma arises when rain falls on dry earth. See also microbial terroir.
La Guerche. S., et al., ‘Origin of (-)-geosmin on grapes: on the complementary action of two fungi, botrytis cinerea and penicillium expansum’, Antonie van Leeuwenhoek, 88/2 (2005), 131–9. doi: 10.1007/s10482-005-3872-4.
