WHY DOES RAIN SMELLS GOOD BUT TASTES BAD

We are all probably familiar with the refreshing scent of rain. But have you ever tasted it?

Adam Ragusea decided to take a closer look at the natural components behind the refreshing scent of rain. “So in this little bottle, I have what is probably one of your most favourite smells in the whole world. And at the same time, it’s probably one of your least favourite flavours. If I smell it, that is the smell of rain — a beautiful, fresh spring rain, the kind of rain that heralds abundance.  It’s the smell of a wet garden. But if I put a  little bit of it on my hand and then taste it,  that is the flavour of dirt, mud,  grossness. What even is this?"

To explore why the scent of rain is pleasant but the taste horrible, Ragusea consulted with perfumer Harrison Sherwood. Sherwood went on to describe the flavour of rain and identified the scent of beetroot and cod. This is a very unusual pairing, however there is a reason to it. This pairing is due to the chemical compounds of Geosimine, which is a natural bicyclic terpene released by bacteria.

“Chemically, it is a bicyclic alcohol and a terpene, or actually I think it’s a  terpenoid because it has oxygen in it. And as is the case with many such terpenes and terpenoids  from the food and drink world, we are very sensitive to this. …Geosimine is a major  component of a mixture of smells known as Petrichor. …Petrichor  encompasses some other smells of rain, …But  arguably the dominant smell within petrichor is Geosimine, which is not made by plants. Geosimine  is made by bacteria. 

Sherwood further went on to explain just how something can smell so good but have the opposite.

“We love it when we smell it outdoors  as a signal of rain. But when we eat,  for example, some river cod and it tastes  muddy, it’s because we’re tasting geosimine.  And most people don’t like that. …When you have tongue signals, plus nose signals,  we call that flavour. That’s now well known, but your brain integrates that in a certain way,  that potentially gives different results in terms of emotion. So Geosimine through nose plus nothing on tongue equals good. Geosimine through nose plus salty taste or whatever equals muddy fish.”

“It all comes from the ground, and the bacteria  that produce Geosimine are in the ground. And so   some of that gets into the food, and there’s  certain foods that tend to concentrate a particularly large amount of Geosimine and beets  are one of them — but also certain greens, like  spinach and some lettuce. And if you ever think  to yourself, this vegetable tastes like dirt, you aren’t wrong.”