sin raised to an art form

𝐩𝐨𝐯: 𝐲𝐨𝐮'𝐫𝐞 𝐚 𝐒𝐡𝐞𝐥𝐛𝐲 𝐰𝐢𝐟𝐞.

John Shelby With His Brother's - Peaky Blinders

Have you ever wondered what is responsible for petrichor, the characteristic after-rain smell? It’s actually the earthy scent of geosmin (C12H22O), a bicyclic alcohol produced by the soil bacterium Streptomyces! Its name is aptly derived from the Greek words  γεω- for “earth” and ὀσμή for “smell”.

Geosmin (1) is synthesised from farnesyl diphosphate (2) by the enzyme geosmin synthase via the intermediacy of germacradienol (3), and is released when these bacteria die. Geosmin is also responsible for the scent of fresh earth, but is most easily detected after heavy rain, which causes the soil to be disturbed and the geosmin inside to be released into the air.

While geosmin is pleasant in very low concentrations, it is a common odoriferous contaminant in drinking water, which can make it taste rather nasty. We are exceptionally sensitive to its taste, being able to detect it at concentrations of 5 parts per trillion - an equivalent of 1 single drop in 4 Olympic-sized swimming pools!

Additionally, it also accumulates in fatty skin and dark muscle tissues of freshwater fish like catfish and carp, giving them a muddy taste. However, this unpleasant taste can be removed by cooking the fish with acidic ingredients, such as lemon juice or vinegar.