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…