Fragrance is a combination of scent molecules that are volatile and evaporate quickly. A perfume, cologne or other personal olfactory products typically contain tens to hundreds of scent compounds, either natural or synthetic. It is the mixture of these components, not their individual molecular weights, that determine a fragrance’s characteristic aroma. The ingredients can be derived from both plant and synthetic sources, with the latter making up the majority of perfumes currently sold in the world. The most common fragrance chemicals include alcohols, esters, aldehydes and terpenes.
In the modern world, perfumes are usually formulated from fragrance bases that are modular pieces built up from essential oils and aromatic chemicals. Typical base ingredients include fixatives, a class of natural or synthetic substances used to slow the evaporation rate, increase perceived odor strength and improve stability; aditive, which is a preservative added to enhance the product’s shelf life; and solvents, a solution of 98% ethanol and 2% water that dissolves the perfume oil and makes it more readily available for application. Perfumes are also often augmented with colorants and other additives, such as phthalates, formaldehydes, toluene, and benzene derivatives that have been shown to cause irritation and allergic reactions.
Modern perfumery began in the fourteenth century with the introduction of a modern type of perfume that blended scented extracts with an alcohol solution. The European Renaissance saw the rise of a culture of personal scent, with men and women donning their favorite fragrances. A craze for donning perfumes reached its height in the sixteenth and seventeenth centuries, and it was not uncommon to find even clothing and jewelry daubed with a person’s chosen scent. In this era, many perfumes were based on heavy, often animal-derived scents.
The perfume concentration level of a fragrance determines how strongly it smells and how long it lasts. The four perfume concentration levels are parfum, eau de parfum, eau de toilette and cologne. Often, a perfume that has different concentrations will actually use different perfume oil mixtures (for example, Chanel No. 5’s parfum, EdP and now-discontinued EdC concentrations are formulated with different perfume oils).
Fragrance extraction methods vary widely, depending on the nature of the plant material and the desired scent. The most common method is distillation, where the materials are heated at high temperatures to capture the desired aromatic compounds. Another extraction technique, called enfleurage, involves soaking the material in carrier oils that serve as solvents to draw out the heavier, more concentrated plant materials.
Once the perfume is formulated, the resulting mix is then tested on a paper blotter called a mouillettes to ensure it reaches the required scent intensity and lasts as intended. The final perfume may be refined several times to ensure its quality, and it can be aged for months or years before being released for sale. The time between initial formulation and final refinement varies by company, but the process of blending, testing and maturing is crucial for a good perfume.