Food smells, specifically the smells of cooking food, are some of the most pleasant and enticing scents known to man.
I know that tastes are highly subjective, but I’m willing to bet that most people find the smells of cake baking or hot apple pie or warm chocolate chip cookies, very pleasurable.
The smells of hot food being cooked are deeply entwined with our sensations, emotions, and everyday experiences. And how could it not be so? The smells of cooking food quickly travels out of the kitchen throughout the surrounding area, beckoning us to eat.
How Does The Smell Of Food Being Cooked Spread So Fast?
The smell of food cooking spreads so fast due to kinetic energy. The heat applied to the food throughout the cooking process excites the food molecules causing them to become airborne and making them travel faster and farther.
The longer answer requires that we delve a bit deeper into the science of smells. So, join me below, as I try my best to simplify the complex chemistry of, temperature, aroma, and how our bodies interpret them.
What Are Smells?
From a chemistry standpoint, smells are a type of sensation or notion of stimulation and perception that is produced by the interaction of organic substances with our olfactory receptors.
The intensity of this interaction depends largely on the volatility (how easily it goes airborne) of the substance since the source of the smell must enter a gaseous state that can eventually reach our nose, and thus be perceived.
This is because our nose is lined with specialized cells that have a direct connection to our brains, where smells are interpreted.
Now you can begin to understand how the smells of hot food can be transported so quickly. The heat from cooking makes the microscopic diffusion of molecules become airborne quicker. They then spread through the surrounding environment until they find their way to our sensitive noses and work their way to our brains, where we perceive them.
How Do We Perceive Smells?
The phenomena behind our brain’s perception of different smells is highly complex, but it can be simplified somewhat into three important aspects: intensity, qualitative description, and appreciation.
The relationship shared between a smell’s concentration and its perceived intensity is well known by science. This is called the odor detection threshold and it has been detected and measured extensively for a dizzying number of substances.
For example, we know that some substances can be detected in airborne concentrations as low as a few parts per trillion. However, this number varies widely across different substances.
Qualitative description of smells is also very complex because perception is highly subjective.
Humans are believed to have the capacity to detect up to 10,000 different odors. However, most of us will only ever become exposed to a much smaller quantity in our lifetimes.
Even then, the smells we do perceive regularly, like those of food being cooked, will be described differently by different people. This is so because the qualitative description of scents is influenced by both cultural and personal biases.
Nevertheless, scientists have been able to create a general classification of smells. There are 10 main categories of smells: fragrant, woody, fruity, minty, sweet, pungent, and putrid, amongst others. These different categories combine in fantastically complex ways to make up the scents we appreciate, especially those of food being cooked.
This is quite impressive when you consider that humans have a relatively weak sense of smell compared to other animals like dogs, rodents, etc.
Smelling The Smells of Food Being Cooked
Now that you have a better understanding of how the human sense of smell works and interprets the aromas and odors we encounter daily, we can return to our original question: how does the smell of food being cooked spread so fast?
The heat from cooking causes the molecules of air around the food to move faster and travel farther out. This is known as the thermal expansion of gasses. When food is cooked, heat will excite the molecular compounds of the food itself, which launches them into the air with a high degree of energy. These gases then mix in the expansion of the air around the food as it gets hot.
Cold food will still produce smells, just ask somebody cutting up onions still cold from the fridge. However, the smell of cold foods does not expand or spread as quickly as that of foods being cooked because the air around it is not moving as much.