Like a musical composer, a perfumer designs fragrances by combining many "notes", or individual scents, with fixatives that keep the scents from dissipating. Many perfumes are quite complex and are the result of the skillful mixing of dozens of notes.
Notes can be grouped into scent families called "series." For instance, musk, castoreum, and civet oil all fall in the animal series. Some of these notes can be obtained from very different sources. For example, carnation notes can also be extracted from clove oil.
About 60% of all notes used in the perfume industry are now synthetics, but naturals are used if their extraction is inexpensive, or if a suitable synthetic counterpart is not available. Natural perfume notes can be divided into five categories based on how they are extracted from their sources:
Concretes, thought to be the purest scents, are obtained by steeping flowers or spices in a solvent that draws out the fragrant oils.
Absolutes are obtained by mixing a concrete with an alcohol and then evaporating the mixture. Most perfumes are made with absolutes. The alcohol that is taken off during the evaporation carries with it some fragrance and is often added to colognes or lotions.
Tinctures are made by chopping a fragrant substance in alcohol. This mixture is then heated and filtered. Civet, castoreum, and musk are often used in tincture form.
Distilled oils are obtained by exposing flowers or herbs to very hot steam. The steam draws off fragrant oils, which rise to the surface when the steam is condensed. Distillation is the cheapest and therefore most common way of extracting scents, but the heat can destroy some delicate fragrances.
Expressed oils come directly from plants. An example of this is the fragrant oil that can be squeezed out of orange peels.