What is it that makes us like an aroma?

Humans can distinguish more than 10,000 different smells (odorants), which are detected by specialized olfactory receptor neurons lining the nose.... It is thought that there are hundreds of different olfactory receptors, each encoded by a different gene and each recognizing different odorants.
From Molecular Biology of the Cell

Smell is a very powerful sense. In order for you to smell something, molecules from that thing have to make it to your nose. Everything you smell, therefore, is giving off molecules - whether it is food cooking, garlic, a favourite fragrance, a piece of fruit or whatever. Those molecules are generally light and easily evaporated in the air, where they then float into your nose.

At the top of your nasal passages behind your nose, there is a patch of special neurons about the size of a postage stamp. These neurons are unique in that they are out in the open where they can come into contact with the air. They have hair-like projections called cilia that increase their surface area. An odour molecule binds to these cilia to trigger the neuron in your brain and cause you to perceive a smell.

Each of the hundreds of receptors are encoded by a specific gene. If your DNA is missing a gene or if the gene is damaged, it can cause you to be unable to detect a certain smell. For example, some people have no sense for the smell of camphor.

When you smell things like fruits or flowers, what you are in fact smelling are the esters evaporating from the fruit or flower. Esters are organic molecules. For example, the ester that gives a banana its smell is called isoamyl acetate, and the formula for it is CH3COOC5H11. The primary smell of an orange comes from octyl acetate, or CH3COOC8H17. Esters can now be made artificially, and that is where artificial flavours come from.

So what makes us like different aromas? 
Is something triggered in our brain when we smell things? When we were running around the countryside and living in caves smells would alert us to danger and help us find food, but we don’t use those skills now.


I know why I like certain fragrances and it is because of my memories, certain things remind me of happy times and because they do I enjoy using them in my products. 


Do you have a favourite “smell” and do you know why it’s your favourite?