Why food smells more when it gets heated?


I’m not even talking about more “complete” heating, like frying or searing, which makes more profound changes to the ingredients. I’m talking about simple stuff like when you reheat food that was in the fridge. A couple minutos ago, for example, I got myself some soup from yesterday. When I opened the recipient it was in, It smelled pretty much nothing. Also it was pretty cold, as it was in the fridge. Then I put it on the stove and soon enough one could smell it’s seasoning from all around the apartment. What influence does heat produce to the smellability of things?

In: 5

Smell is the food particles that get to your nose through the air. You get more evaporation from hotter food (even before boiling), so it smells more.

**TL;DR:** *It is a triple-whammy that has to do with how heating affects solids and liquids. There’s convection, there’s melting/vaporization, and there’s sometimes humidity… and all of them can work together to make your house smell yummy.*


Cold soup is often a lot “thicker” than hot soup, and that causes a lot of its scents to be trapped.

When you put your cold soup on the stove, the warming process raises the temperature of BOTH the scent chemicals that create the smell, and the oils, fats or liquids in which they were trapped. The oil becomes thinner, the water starts evaporating a little faster, and the fats turn to liquid. All of these allow the types of molecules that we can smell to better escape the previously cold mass that they were stuck in, and spread through the warming nearby air.

Further, the liquids in the warming soup begin to circulate within the pot as its temperature continues to rise – this is called thermal convection – and that circulation brings more of the warming scent molecules to the surface and releases them into the air. (That circulation also applies to the warming air above the pot too, so those chemicals float upward and spread throughout the room more easily.)

If you heat or boil enough water, it also raises the humidity in the area, and that can make it easier to smell a scent too. For example, if you walk into a bathroom where someone just had a long hot shower, you can really smell the shampoo they used. This usually doesn’t apply unless you’re slow-cooking a bunch of soup over a long time, but if you open your microwave, say, and a bunch of steam comes out, it’ll amplify any smell you have in there for sure.

Smell is just tiny bits of the thing you are smelling getting to your nose. It’s literally “I can smell chocolate – because there are literal bits of chocolate floating about in the air and getting into your nose.

Ok; so have a think about water. When it is cold, you see nothing over the water. But get it hot. What do you see? Tiny bits of water in the air.

Hot things emit more bits off them. That means hot things smell more.