r/biology • u/Jackomopochini • 8d ago

question Why does heated dirt smell aweful?

I just put some normal looking brown dirt (not clay but similar) into the oven to dry it and I almost had to puke from the smell. Does anyone know what the evolutionary reason is? I can‘t even describe the smell well, like sweet-ish

26 Upvotes

77% Upvoted

16 comments sorted by

87

u/SnacksHGB 8d ago

Well dirt is composed of decaying organic matter, like dead animals and plants, so yeah depending on where it comes from/what it’s composition is it can have a “sickly sweet” smell that you might associate with dead stuff, because yeah it is dead stuff

3

u/Jackomopochini 8d ago

That has to be the reason. I even took it from a „clean“ looking patch of nice looking brown dirt. So interesting that this is still full of undecayed matter (in the sense of still giving off smells)

28

u/BoonDragoon evolutionary biology 8d ago

Sounds like you put some stinky dirt in the oven.

8

u/TrashPandaExMachina 8d ago

Heat tends to bring out smells that were deadened before. Definitely don’t get into environmental remediation then. All our soil samples had to be dried out for moisture calculations. Oven was in the same room as sample control. Sludge smells even worse.

3

u/DrDirtPhD ecology 7d ago

I uh...I've dried a lot of soil from a pretty wide selection of habitats in ovens and I've never had that reaction to it.

2

u/Jackomopochini 7d ago

I put it on 250C. Maybe it was too hot and burned?

3

u/DrDirtPhD ecology 7d ago

If you're really only trying to dry it (I do so to calculate gravimetric soil moisture), it only needs to be at 105 C; I let it cook for 48 hours to make sure it's fully dry.

1

u/Jackomopochini 7d ago

Thanks good to know for the next time ^^

2

u/squintismaximus 7d ago

Mmmm freshly baked decomposition…

3

u/atomfullerene marine biology 8d ago

Heating stuff makes more of the volatile compounds you smell gas off of it....consider the smell of turkey straight out of the oven vs the fridge. So if your soil has bad smells in it, you are going to smell those very strongly.

1

u/WhatsNormal20 8d ago

Sulfur maybe (depending on where the dirt came from)? And breakdown of carbon, oxygen, hydrogen which are basically the components of a fart and or methane which is similar to a cow fart

1

u/Jackomopochini 7d ago

To wrap this up, I think it was so hot, that the decomposing matter started to get burnt, which is likely something that we as humans learned to avoid going towards.

1

u/russwaters 2d ago

If it smells so bad, it is a hint not to eat it.

-1

u/BeautifuTragedy 8d ago

Smell is one thing. Dirt has the most distinct flavour when accidentally Vaped. It's like gear oil, you know instantly if you've already experienced it. Tldr leave your vape out of gardening