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?