Although every element of a dish is important in creating its unique flavour, aromas are the fast and furious of them…

Although every element of a dish is important in creating its unique flavour, aromas are the fast and furious of them all. They launch the flavour attack even before we visually engage with the dish. Imagine returning from work and catching the first whiffs of dinner being cooked as you step into the hallway. The aroma welcomes you home and offers a comforting preview of the meal before you even sit down to enjoy it.

The sense of smell (olfaction) is by far the dominant contributor, typically accounting for 75-90% of what we perceive as “taste” or flavour. This becomes painfully obvious when a cold or flu temporarily deprives us of this channel, leaving all food tasting bland and uninteresting. In rarer cases, people can lose this ability permanently or for extended periods. This condition is known as anosmia – the inability of the olfactory receptors to register odours.

When we “taste” food through smell, hundreds of volatile molecules travel from the back of the mouth up into the nasal cavity, where they bind to odour receptors. A single aroma can bind to multiple types of receptors, and a single receptor can recognise many different aroma molecules.

Thanks to this system, humans can distinguish up to a trillion different aromas. It is no surprise, then, that olfactory receptor genes form the largest single family in the human genome. Out of roughly 19,000 genes, nearly a thousand are dedicated to olfactory receptors – about 5% of all our genetic information.

This olfactory pathway is unique not only because of its remarkable ability to detect fine aromatic nuances, but also because it speaks directly to the brain. It is the only sensory channel that communicates with the cortex, amygdala (emotion), and hippocampus (memory) while bypassing the thalamus – the brain’s sensory gateway responsible for filtering, processing, and integrating sensory input. This direct route is why certain smells can trigger powerful emotions and vivid memories with little conscious filtering. All other senses – vision, hearing, touch, and taste – are routed through the thalamus.

We are born with certain predispositions toward particular flavours, shaped by our mother’s food choices during pregnancy. Unbeknownst to us, we enter the world already steeped in a specific food culture. Throughout life, we continue to expand our personal aroma library through experience and training. While genetic factors can create specific aroma intolerances (coriander being the most commonly cited example), most of our food preferences and behaviours are learned*.

Most of the aromatics we use to uplift our dishes are of plant origin. Spices, herbs, citruses, and flowers form an unrivalled aromatic quartet that we deploy to create flavour. Every coriander seed or basil leaf contains not just one aromatic molecule, but a complex blend that gives it its distinct personality.

These aromatic similarities form the basis of flavour affinities. In other words, ingredients tend to pair well when they share key aromatic compounds. Strawberry and basil, for example, complement each other beautifully because they share several important molecules, most notably methyl cinnamate (sweet, fruity, balsamic), estragole (sweet, anise-like, herbal), various green notes (hexenal compounds), linalool, and other terpenes**.

Biologically, aromas serve as the plant’s survival mechanisms. When experienced in concentrated or pure form, they can be quite pungent or even irritating – try chewing on a whole clove or a vanilla bean. During these processes, chemicals known as volatile organic compounds (VOCs) are released, primarily to fend off attacks by animals or microbes. Plants often launch pre-emptive strikes by sending these molecules into the air. This is why aromatics are extremely volatile – meaning they easily evaporate and turn into gas at normal room temperature and pressure.

To transform plants’ weapons into our pleasures, we apply the principle of dilution. When cooking, we either combine these flavourings with other ingredients (such as oils or vinegars) or use gentler extraction methods like toasting or drying. Knowing how to properly extract and balance the flavour from each aromatic is one of the key skills in preparing fragrant food.

* Wilson, Bee (2015). First Bite, How We Learn To Eat. 4th Estate, London.

** Coucquyt, Peter et al. (2020). The Art & Science of Foodpairing. Mitchell Beazley.

Read more about food from Irina Mikhailava: We first eat with our eyes or The art of flavour: introduction