'Your sense of smell is your most primal sense and exerts surprising influence over your thoughts, emotions, moods, memories, and behaviors. Scents are experienced long before words.
This is why it’s nearly impossible to describe them with language. Olfaction is different from your other senses, processed through different pathways in your brain.
For other sensations such as sounds and visual images, sensory input is delivered straight to your thalamus, which you can think of as “the big switchboard” in your head. From there, data goes out to your primary sensory cortices.
But smells are different. Before reaching your thalamus, they first wind their way through other regions of your brain, including areas controlling memory and emotion. So with scents, you have all this extra processing even before you have conscious awareness of the scent.'