Fragrance or perfume is a mixture of chemicals that have pleasant or distinctive smells. It consists of essential oils or aromatic chemicals, and may also contain fixatives to slow the evaporation rate. It can be applied to the skin or ingested. Modern perfumes and colognes usually contain several hundred ingredients. Some of these are natural; others are synthetic. Many of the scent components in a perfume are named after the plant or animal that is derived from or created to imitate its smell. The industry uses several different classification systems to classify perfumes and colognes, including scent family and scent family subtype, as well as more general categories such as floral, oriental, woody, or citrus.
Fragrances have been used by both men and women for thousands of years. The Egyptians used perfume for ritual purposes, and the Etruscans wore scented oils to mark social status. In the Renaissance, perfume was considered an art form and even a symbol of femininity. It was commonly believed that wearing perfume could prevent illness, and a perfume bottle was often placed in the grave of a dead woman to accompany her into the afterlife. In the mid-nineteenth century, however, germ theory gained support and perfumes fell out of favor with the public. The public image of perfume shifted from being a symbol of beauty to being an indication of filth. As a result, perfume use became more modest among men of higher social standing. By the early twentieth century, only prostitutes and those of lower social status wore perfumes.
The ingredients in a perfume are blended according to the fragrance company’s brief, which is a description of what they want the perfume to smell like. The perfumer must create a fragrance that meets this brief while balancing the perfume’s concentration. This can be a difficult task because the composition is highly volatile, and the perfume will change dramatically with body temperature changes.
A perfume’s ingredients include top notes, middle notes and base notes. Top notes are the light scents that are perceived immediately after a perfume is applied and evaporate quickly. Middle notes are the middle of a perfume’s structure and appear just prior to the top note’s departure from the skin. Base notes are the deeper scents that linger for 30 minutes or more and provide depth to a perfume.
Unlike the natural perfumes of old, most of the scent ingredients in contemporary perfumes are manufactured through chemical processes. In the past, important natural perfume components were sourced from animals such as whales and civet cats; now, the scents of these animal oils can be mimicked using synthetic molecules. These chemical compounds are often referred to as “notes” in a perfume because they are an accord of the scent that is repeated throughout the perfume. For example, the molecule calone imparts a fresh ozonous metallic marine scent and is found in many fragrances. Regardless of the source of their odorants, all perfume ingredients must be carefully screened for safety. The fragrance industry maintains a rigorous system of self-regulatory quality assurance, based on the Research Institute for Fragrance Materials (RIFM).