Volatility grouping
Fragrant materials are listed by Poucher in order of volatility and are grouped under respective evaporation coefficients (perfume notes) that range from 1 to 100.Top notes
Top notes are otherwise called the head notes. Perceived immediately upon 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 the product. The scents of this note class are usually described as "fresh", "assertive" or "sharp". The compounds that contribute to top notes are strong in scent, very volatile, and evaporate quickly. Although not as saliently perceived, the heart and base-notes contribute much to the scent in the top notes.Middle notes
Also called the "heart notes", the middle notes are the scent of a perfume that emerges just before the top notes dissipate. The middle note compounds form the "heart" or main body of a perfume and emerge in the middle of the perfume's dispersion process. They serve to mask the often unpleasant initial impression of base notes, which become more pleasant with time. The scent of middle note compounds is usually more mellow and "rounded". Scents from this note class disappear anywhere from twenty minutes to one hour after the application of a perfume. Lavender andBase notes
Also called the "soul notes", base notes are the scent of a perfume that appears close to 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. Compounds of this class are often the fixatives used to hold and boost the strength of the lighter top and middle notes. Consisting 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 dry-down. Some base notes can still be detectable in excess of twenty-four hours after application, particularly the animalic and musk notes.See also
* * Solid perfumeReferences
{{Perfume Perfumery Olfaction