The performance of a fragrance can be understood based on the volatility and tenacity of the raw materials from which it is composed. Any fragrance can generally be broken down into its top, middle and base notes, each of which has a different role to play in the arc of a fragrance’s life cycle:
The scents that are perceived immediately on application of a perfume/fragrance are considered the top notes of the fragrance. These notes help to create the initial impression of the fragrance and in turn begin to draw in the customer's attention. The volatile nature of these components make them seem to “jump off the page”, but they will be much less evident in the dry-down of the fragrance, an important thing to consider for the fragrances final application.
The middle notes of a fragrance help to determine the character of that fragrance. Whether it’s floral, woody, spicy, green, or fruity, if you had to give a one-word description of a fragrance, you’re probably talking about the middle notes. The middle notes, together with the finishing touch of the base notes, are the main theme of a fragrance.
As the fragrance continues to evolve, the base notes become more evident. These components tend to have the highest evaporation points, and are therefore most represented in the dry-down of a fragrance. Base notes can add depth, warmth, and an exotic effect to the longevity of a perfume.
But remember, these three classifications are really just placeholders in the Perfumers’ lexicon, used to aid discussion and to keep everything ordered in the Perfumer’s mind. The evolution of a fragrance is not a strictly linear progression. The top, middle, and base notes interact and intertwine to create the fragrance as a whole. None of them can stand alone, they can only perform and shine in harmony together like a symphony orchestra.