Definition: flavour and smell

How do smell and taste work?
Smell and taste are chemical senses. This means that olfactory and gustatory sensations are caused by the stimulation of certain sensitive nerve cells in the nose or mouth by specific molecules.

Odour receptors (olfactory neurons) are stimulated by chemical particles suspended in the air around us (the smell of fresh bread, freshly roasted coffee or a bouquet of flowers, etc.). All the cells that receive different odours are located at the top of the nasal cavity.

When an olfactory neuron is stimulated, it produces an electrical current that is transmitted to the brain via the fibres of the olfactory nerve. In the brain, these olfactory perceptions are analysed, recognised and memorised. Humans can recognise more than 10,000 different smells.
Other sensory nerves:
Next to the olfactory and gustatory nerves is a third nerve: the trigeminal nerve, which is sensitive to heat, cold, irritants such as pepper, and consistency (liquid, solid or gaseous). The trigeminal nerve is divided into three branches: the ophthalmic nerve, the maxillary nerve and the lingual nerve.

The flavour of a food is composed of the sum of five different taste stimuli: its temperature, its irritant properties, its smell, and its consistency. It is the smell of a food that probably contributes most to its characteristic flavour. Why do foods lose their flavour when your nose is blocked during a bout of flu or a cold? When we eat, smells pass through the back of the nose (retronasal olfaction).

Heat and light radiation break down compounds such as spices. Their extracts are best preserved away from light and moisture, i.e. in opaque containers and in cool, dry places. The same applies to wines.