Eli5: Why does cold food not emitt any powerful scent?
In: Biology
To smell something, particles from that thing need to actually float through the air and make it to your nose.
Warm foods, or hot steaming foods, have the energy to expel those particles and let them become free floating, possibly carried by hot rising steam, or just floating on their own.
Cold things don’t have that, there isn’t any real energy to propel the particles through the air.
Basically, it takes energy to get particles from the food to your nose, cold things have less energy than hot things, and so those particles that need to hit your nose arent very likely to make it there.
Heat turns water on the food into water vapour, water vapour coming off food can carry the smells of food easily into our noses.
It has to do a bit with evaporation. Literally, the compounds need to vaporize to become airborne. The warmer the food the more likely it is to vaporize.
It’s why we swirl the wine in a glass. It increases convection and surface area promoting vaporization of the wine molecules allowing us to smell more.
Most of what we smell are VOCs – volatile organic compounds. They are various compounds that dissolve in air and we can smell them if the concentration is high enough. Most of the VOCs that make up food smells dissolve into air much better when they are hot. When cold they mostly stay where they are at as opposed to dissolving into the air and floating into our noses.
Because you can’t smell food. You can’t smell any solid. What happens with smell is that molecules evaporate (liquid to gas) or sublimate (solid to gas) and that gas goes up your nose when you breath. Once in your nose the molecules will bind to all kinds of nerves and that is how you smell. This is true of any smell. The process of sublimation and evaporation is faster as the food is hotter. Think how a hot soup puts off steam but a cold one doesn’t. This makes the concentration of sent molecules less in the air so the smell isn’t as intense.
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