To describe the scents perceived in a perfume, we use what are known as fragrance notes.
Fragrance notes are divided into three classes – head notes, heart notes and base notes – on the basis of the “time development of the fragrances” over time, or on the basis of the time of evaporation or persistence of the various fragrances in the perfume.
The combination of the three groups comprises the “olfactory pyramid”, which we use to describe a perfume.
HEAD NOTES: also called “top notes”, are the first notes we perceive when we smell a perfume. They are fresh and light and with a weak persistence; they disappear, in fact, in very few minutes. The most common head notes are those of citrus, aromatic herbs and aquatic or marine notes.
HEART NOTES: comprise the middle notes of a perfume and are those we perceive immediately after the head notes. They have average persistence and last for around 2 or 3 hours. The heart notes give character to the perfume and are generally flowery, fruity or spicy.
BASE NOTES: give holding power and intensify the character of the perfume. We do not perceive them immediately, and even half an hour may pass before we manage to notice them, but they are the notes that persist for the longest because they evaporate very slowly. They can even persist for more than 24 hours and they are often balsamic, boisée or oriental notes.