You may think that you know how to smell. After all, you've been doing it all of your life. Sampling a fragrance, however, is very different than smelling things that you encounter during the course of your day. Many of the odors that you will notice, such as exhaust fumes, hairspray, deodorant,-cut grass, etc., are "single scents". The simple act of breathing brings these odors into your nose, where your brain "matches" them to the odors that you have experienced in the past. Recognizing which odor your are perceiving means that the "match" was successful, and your brain understands that you have smelled this scent before.A fragrance, on the other hand, is a group of scents, or odors, that have been combined. This can get a bit confusing about now, because some of what have just been described as "single scents", like the hairspray example above, contain commercial "perfumes", which are actually fragrances. In order to clarify this situation, you need to know something about music. Music? Yes, music!
Perfumers, and other people who create fragrances, describe scents in the same way that musicians speak of music: in "notes". A single scent molecule is considered as a musical "note". The perfumer blends these scents into a fragrance, in the same way that a musician combines notes into music. For example, the odor of vinegar, or strawberries, would be a "single scent", or "note", for our purposes. Each of these scents is unique, and recognizable.
The average perfume contains about 125 different "notes", or scents, in its formula. By combining these "notes", the individual scents are hidden, and the fragrance is not recognizable or familiar. The fragrance "Old Spice" is a good example of a scent that has no dominate, recognizable odor.
In order for a substance to have a perceivable odor, some of it must be reaching your nose. Chemists describe this phenomena as "volatility". When a substance is "volatile", it means that molecules of the substance "evaporate", or leave the surface of the material, and fly off into the air. Alcohol is "volatile", as are the hydrocarbons that make up gasoline, and both easily evaporate.
Different substances have different rates of evaporation, or "volatility". Some substances evaporate quickly, like the alcohols, while others are much slower, like tree pitches and resins. The most volatile portions of a fragrance are referred to as the "top notes". The slowest substances are called "base notes", or "the dry out". Those substances which are neither top notes, nor base notes, are usually referred to as the "middle notes", or "heart notes".
Classic perfumes contain all three types of "notes", and therefore there is an "evolution" to the scent. In other words, the fragrance "evolves", or changes over time. A good way to understand this process is to picture an orchestra which, during the course of a day, looses members until no sound can be heard. With the loss of an individual orchestra member, the sound produced from that person's instrument no longer contributes to the music, and therefore, the tone of the music changes. So it is with a fragrance.
Since the scent of the fragrance changes over time, the scent that you smell initially is different from the scent that you will smell later, or the one that you will wear. The "top notes" being the most volatile, the scents that they contribute to the fragrance are the most fleeting. When smelling a fragrance from the bottle, or when it's first applied, the "top notes" are the most dominate scents. This is why this initial smelling is the most unreliable, in determining whether or not you will like the fragrance.
The best way to evaluate a fragrance is to lightly mist the air, then quickly wave your hand through the mist. Misting your hand or forearm directly will also work, as long as you remember to allow the alcohol in the fragrance to dry, prior to smelling it. If you were to smell the scent as soon as the alcohol has dried, you would be smelling mostly "top notes". The fragrance has not yet had an opportunity to blend itself with your body chemistry. Allowing the fragrance some time to "marry" with your own body scent will give you the best indication of how the fragrance will smell on you.
