Perfume is a combination of fragrant essential oils or aroma compounds, fixatives, and solvents in liquid form used to give the human body, animals, foods, objects, living spaces, and other materials an agreeable fragrance. Perfume is a highly complex chemical mixture, with from tens to hundreds of ingredients. Perfume is generally a combination of natural or synthetic aromatic compounds, including alcohols, esters, aldehydes, terpenes, and many other types. It may also contain dyes and coloring agents.
Perfumed products have a long history. The first perfumes were probably derived from flowers and other plant parts or from natural animal oils, such as ambergris or deer antlers. In the 9th century, the Arab chemist Al-Kindi wrote The Book of Chemistry, which included more than 100 recipes for perfumes and described 107 methods for distilling plants into fragrant oils. The same book included instructions for making perfume using a still called an alembic, a copper vessel with a wide mouth designed to hold large volumes of liquids.
The modern perfumer’s art and science is much more sophisticated. A perfumer will combine tens to hundreds of ingredients into a composition that is intended to give off a pleasing smell for hours after application. This process is called synthesis.
Contemporary perfumes usually consist of a base of alcohol and glycerol, with the remainder composed of a volatile mixture of fatty acids and essential oils or extracts. The essential oils are combined with a variety of additives to reduce evaporation, increase perceived odor intensity, and add stability. These additives include preservatives, stabilizers, diluents, and diffusion enhancers.
Scents are perceived as a harmonious whole by the nose, and the composition of a perfume is often described in terms of musical metaphors. The composition consists of three structural parts that unfold over time: the top notes (also known as head notes) give an initial impression and evaporate quickly; the middle notes are the main body of the scent and emerge from the evaporation of the top notes; and the base is the final expression and lasts longer than the other notes.
In studies of perfume preferences, women have reported that their mood and the occasion or aim of the perfume influenced their choice. For example, women who were feeling nervous chose a more musky or woody fragrance than those who were relaxed. Mood also influenced the perfumes that women chose to wear at romantic or job interviews.
Several species of animals are known to adorn themselves with a fragrant mixture that is intended to attract conspecifics or distract them from predators. For example, wolves roll themselves in carcasses or feces to mask their own odors and to camouflage themselves as they approach prey. The purpose of such self-adornment in humans is unclear, but it may serve to mask unpleasant odors and to mark territory. The use of perfume is also widely accepted as a mark of status in society. In the eighteenth century, sweet floral blends became associated with femininity and sharper, woody scents were deemed masculine.