Perfumes are complicated products, often containing many different fragrances. As you wear a perfume, you will often find the fragrance changes. This is a result of the fragrances within the perfume evaporating at different rates. For simplicity the changing aroma is classified into one of three groups. In reality it is a lot more complicated than that, but Top Middle and Base notes have become a common way of describing perfume fragrances.
These are perceived immediately upon applying a perfume. They consist of small, light molecules that evaporate quickly. They form your 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.
Typical top notes include citrus elements (bergamot, lemon, orange zest), light fruits (anise, berries, grapefruit) and fresh herbs (basil, sage, lavender).
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 aromas form the "heart" or main body of a perfume. Not surprisingly, the scent of middle note compounds is usually more mellow and "rounded". Middle notes typically disappear anywhere from twenty minutes to one hour after the application of a perfume.
Scents such as lavender, rose, cinnamon, ylang ylang, lemongrass and neroli are all common and recognisable heart notes.
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. The base note fragrant molecules evaporate slowly, and are typically rich and "deep" and are usually not perceived until 30 minutes after the application of the perfume.
Common base notes include cedarwood, sandalwood, vanilla, patchouli and musk. Some base notes can still be detectable in excess of twenty-four hours after application, particularly the animalic and musk notes.