geo·​smin | \ jē-ˈō-smən How to pronounce geosmin (audio) , ˈjē-ō- \
plural geosmins

Definition of geosmin

: a volatile, organic compound C12H22O that is formed especially by soil-dwelling bacteria (such as streptomyces) and aquatic cyanobacteria and that may contribute to the earthy, pleasant odor of petrichor or impart a disagreeable, musty taste and odor to drinking water and certain fish In the test kitchen, we too have noticed a mysterious muddy flavor in some catfish and tilapia. … When the fish swim in the geosmin-rich water, they consume the compound as they ingest the algae.Cook's Illustrated Geosmin can be detected by a human nose at miniscule concentrations, as low as just a few parts per trillion, [Kelley Dearing] Smith said.— James Bruggers

Note: Geosmin is a tertiary alcohol having a hydroxyl group (-OH) attached to a carbon atom that has three other carbon atoms attached to it.

First Known Use of geosmin

1965, in the meaning defined above

History and Etymology for geosmin

Greek gē-, geō-, combining form of "earth" + osmḗ "odor" + -in entry 1 — more at geo-, anosmia

Note: Term introduced by the American biochemist Nancy N. Gerber (1929-85) and the French-born American biologist Hubert A. Lechevalier (1926-2015) in "Geosmin, an Earthy-Smelling Substance Isolated from Actinomycetes," Applied Microbiology, vol. 13, no. 6 (November, 1965), pp. 935-38.

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The first known use of geosmin was in 1965

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Cite this Entry

“Geosmin.” Dictionary, Merriam-Webster, Accessed 8 Mar. 2021.

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