Perfume is a mixture of volatile liquids and oils which are sprayed on the skin to produce a fine and prolonged scent. The oil-based fragrance is usually diluted with alcohol to increase its longevity and stability. Perfumes typically contain from ten to hundreds of ingredients. These include essential oils derived from natural aromatic plant extracts; synthetic aromatic chemicals classified by their structural group (e.g., alcohols, esters, aldehydes, and terpenes); fixatives, which slow the evaporation rate of the perfume; and solvents, which dilute the perfume to improve its viscosity and odor intensity. Modern perfumes also frequently include colorants and antioxidants to enhance their aesthetics.
The Grasse region of France, Sicily, and Calabria in Italy were early centers for perfume production because they provided abundant aromatic plants. Today, France and Italy continue to be important suppliers of the high-quality raw materials needed for modern perfumery.
In addition to flowers, herbs, grasses, spices, fruits, woods, roots, resins, balsams, and leaves, perfumers also use animal secretions and fatty compounds such as ambergris, myrrh, and vanilla. Traditionally, many perfumers employed macerations and distillation techniques to obtain the essential oils from these raw materials. Today, most of these oils are extracted using a process called expression, in which the material is squeezed or pressed to release the fragrance molecules.
A large portion of the odorants used in perfume are secondary metabolites produced by the plant as protection against herbivores, infections, or to attract pollinators. For this reason, the odors attributed to different parts of the same plant can vary widely. For example, the leaves and seeds of coriander offer different fragrances. In general, flowers provide the largest source of perfume aromas. For this reason, perfumers often use several flowers in a single formula.
Fragrance companies often publish the list of odorants in a particular perfume. Those odorants are organized into family groups to form what is known as a “fragrance pyramid”. This structure is based on the relative concentration of the various aromatics in a perfume. The higher the concentration, the stronger and more expensive the perfume.
Perfume is often perceived as a desirable commodity, especially by women. Many men likewise appreciate the use of perfume, particularly those containing certain aphrodisiac chemicals known to promote sexual excitement and pleasure in the recipient. However, it is difficult to determine whether a specific perfume actually does possess such aphrodisiac properties.
In addition to the aphrodisiac effects of some perfumes, others are thought to be emotionally soothing, refreshing, or uplifting. These properties make perfumes valuable in a variety of settings and circumstances. Some perfumes, particularly those containing jasmine and ylang-ylang, are even thought to reduce depression in some patients. In addition to perfume, many people adorn themselves with other types of scented substances such as cologne and body sprays.