Perfume is described in a musical metaphor as having three notes, making the harmonious chord of the scent. The notes unfold over time, with the immediate impression of the top note leading to the deeper middle notes, and the base notes gradually appearing as the final stage. These notes are created carefully with knowledge of the evaporation process of the perfume.
The scents that are perceived immediately on application of a perfume. Top notes consist of small, light molecules that evaporate quickly. They form a person’s initial impression of a perfume and thus are very important in the selling of a perfume. The compounds that contribute to top notes are strong in scent, very volatile, and evaporate quickly. Citrus and ginger scents are common top notes. They are also called the head notes and usually last about five minutes.
The scent of a perfume that emerges after the top notes dissipate. The middle note compounds form the heart or main body of a perfume and are usually more mellow and rounded. Lavender and rose scents are typical middle notes. They are also called the heart notes and typically last about 10 to 60 minutes.
The scent of a perfume that appears after the departure of the middle notes. The base and middle notes together are the main theme of a perfume. Base notes bring depth and solidity to a perfume and consist of large, heavy molecules that evaporate slowly. Compounds of this class of scents are typically rich and deep and are usually not perceived until 30 minutes after the application of the perfume or during the period of perfume drydown.
As a fragrance’s more volatile components – the topnotes and midnotes – evaporate, the endnotes linger and carry the body of the fragrance. All fragrances change as they dry down, and all fragrances are affected by each person’s unique skin chemistry, but the fragrance should remain true in character. Perfumers use fixatives (aromatic ingredients that fix or prolong scent) in the drydown to ensure a scent’s longevity.