Perfumes are complex compositions of chemical compounds and synthetic or natural ingredients. Their true formulae are closely-guarded secrets. However, even if they were made known to the public, they would be almost incomprehensible. Instead, the complex arrangement of a fragrance’s different aromas is broken down using musical metaphors and vivid imagery. Rather than explore the fragrance’s literal composition, enthusiasts describe the sensual experience it provides. Perfumery is not unlike wine in that sense. Even for amateurs, the joy is discovering the bouquet and identifying its character.

Have you noticed how a perfume doesn’t smell the same throughout the day? This is because you can’t smell all of a fragrance’s notes at any one time. The different compounds used to devise the notes have different levels of volatility, which are sometimes referred to as coefficients. This is caused by the skin’s heat and the way a fragrance dries and evaporates off it. The compounds in a fragrance evaporate at different speeds rather than all at the same time. As this happens, the fragrance reveals different notes to the wearer. The first notes that you can smell are considered the most volatile because they quickly fade away. Once they’re gone, something else seeps through and takes it places. The process continues as the notes diffuse until you reach last layer of notes that tenaciously lingers for hours. This is often referred to as a fragrance’s life-cycle. A life-cycle is quite simply the way a fragrance “cycles” through its life. It is the succession of notes until the perfume expires completely. Certain fragrances cycle through their notes one after the other in a straight-forward way. Other fragrances can be quite complex as their notes will overlap with one another to form different accords. Life-cycles are often assessed subjectively. Some enthusiasts prefer complex journeys of notes whilst others are partial to a simple, linear evolution.

The notes are then stacked on top of each other like layers, which serve to indicate the life-cycle’s chronology. This takes the form of a triangle but is colloquially referred to as a pyramid.

Each layer metaphorically supports by the one above it. The time between each phase varies drastically between fragrances, which relies on the different compounds and their volatility. Some types of compounds have similar properties and their volatility can classed together. This can provide a better idea of what to expect from particular fragrances from different families. Below is an expanded perfume pyramid that has been filled with different note types and a few examples.