The fragrance pyramid: top, heart and base notes explained

The fragrance pyramid describes a perfume over time. Top notes are what you smell in the first seconds, carried by the materials that evaporate fastest. Heart notes, also called middle notes, take over next and give the fragrance its main character. Base notes, made of the slowest-evaporating materials, are the last to leave your skin or your scarf.

The pyramid is a handy way to read a perfume, and it's also a simplification. All three tiers are present from the first spray, reference sources don't always put a material on the same tier, and some fragrances are built to barely change at all. Read it, then check it for yourself with a few strips of paper.

What do top, heart and base notes describe?

Top, heart and base notes name three moments in the life of a single perfume. Wikipedia's article on perfume notes describes top notes as small, light molecules perceived as soon as the perfume goes on, heart notes as the main body that emerges just before the top fades, and base notes as large, heavy molecules that bring depth and solidity. It gives citrus and ginger as common top notes, lavender and rose as typical heart notes, and says some base notes, particularly animalic and musk notes, can still be detected more than twenty-four hours later.

French perfumers use their own vocabulary for the same idea. The glossary of the Société française des parfumeurs (in French) calls the top note the départ, the departure, and says it is the heart note that sets the theme of the perfume, while the base is what lasts once the top and heart have evaporated.

Why does a perfume change over the course of a day?

A perfume changes over the day because its materials evaporate at different speeds. Small molecules lift off first and large ones linger, which is why the same Wikipedia article says base notes are usually not perceived until 30 minutes after application. It adds that base-note materials often act as fixatives, holding and boosting the strength of the lighter top and heart notes.

The scale behind the pyramid has a very British story. William Arthur Poucher (1891-1988), a research chemist with Yardley who was also one of Britain's leading mountain photographers and guidebook writers, published the textbook Perfumes, Cosmetics and Soaps in 1923 and kept revising it. Its ninth edition, from 1993, ranks raw materials on an evaporation coefficient from 1 to 100: 1 to 14 for top notes, the most volatile, 15 to 60 for heart notes, and 61 to 100 for base notes.

Musks are the textbook base note. Wikipedia's article on synthetic musks says they are used as fixatives, supply the base note of many perfume formulas, and that most musk used in perfumery today is synthetic.

Where do lemon, jasmine, sandalwood and musk sit in the pyramid?

Lemon, jasmine, sandalwood and musk don't always land on the same tier: it depends on which reference you open. The table compares three encyclopedia articles. Wikipedia's main Perfume article, for instance, lists sandalwood as a heart note, while the worked example in the French-language Wikipedia article puts it in the base, and lavender moves from top to heart between the two English articles.

The differences suggest that a material has no fixed floor. Where it sits depends on the composition around it, so a pyramid describes one perfume, not an ingredient in general. Citrus is the steadiest case: all three sources put it at the top.

What does the fragrance pyramid leave out?

The fragrance pyramid leaves out, first of all, the overlap. Wikipedia's notes article points out that heart and base notes, though less obvious at first, contribute a lot to how the opening smells, and that the presence of one note can alter the perception of another. The same top notes won't smell quite the same over two different bases.

It also leaves out what the words really stand for. The notes article says the idea of notes is used primarily for the marketing of fine fragrances, and the Perfume article lists "seawater" among its heart notes: a note often names an impression rather than a material you could buy in a bottle. Magazine guides, Mademoiselle Bulle's guide to choosing a perfume among them, walk readers through the pyramid tier by tier, and it's a good map as long as you read it as a map.

Finally, it leaves out which version you're holding. According to the Perfume article, an eau de toilette may be tweaked to contain slightly more top notes or fewer base notes than the eau de parfum of the same name. Before comparing two pyramids, check which fragrance concentration, from extrait to eau de cologne, each one refers to.

What is a linear fragrance?

A linear fragrance gives the same impression from the first minute to the last, so it has almost nothing to stack into tiers. The French perfumers' glossary defines a linéaire composition in just those terms: one that keeps the same olfactory impression all the way through its evaporation.

The extreme case is a perfume made of a single material. Wikipedia's article on Iso E Super, a woody molecule created at International Flavors & Fragrances in 1973, cites Molecule 01, launched by Escentric Molecules in 2006 and made entirely of diluted Iso E Super. A pyramid has little to describe in a perfume like that, even though commercial Iso E Super is itself a mixture of more than twenty isomers.

How do accords blur the tiers of the fragrance pyramid?

An accord blends several materials into one impression, and it rarely stays on a single tier. The Perfume article borrows the musical image directly: three sets of notes that together make one harmonious accord.

The chypre family shows it well. The Perfume article names it after François Coty's Chypre of 1917, built on an accord of bergamot, oakmoss and labdanum. On a pyramid, bergamot would sit at the top and oakmoss at the bottom, where the French article places the mossy, woody base of chypres. Yet the family takes its name from the accord as a whole: a perfume is composed around an accord, and the pyramid tells it in slices.

Exercise: follow the fragrance pyramid on a blotter

This exercise lets you watch a fragrance pyramid unfold without putting anything on your skin. You need a day, a perfume you already own and a few strips of paper. In French they're called mouillettes, and the French perfumers' glossary describes them as thin strips of very absorbent paper made without glue; in English you'll hear blotters or smelling strips. Thick watercolour paper or a coffee filter cut into strips will do.

1. Cut four strips about a finger wide and write on each the time and what goes on it.
2. Spray your perfume once on the tip of the first strip, away from your face. Rub a piece of fresh lemon peel on the second, put a drop of vanilla extract on the third, and leave the fourth blank as your control.
3. Smell all four straight away, then after fifteen minutes, after an hour, in the evening and the next morning. Each time, jot down three words per strip without hunting for the perfect one.
4. Between rounds, stand each strip in its own glass so they don't touch, away from cooking smells.
5. Next morning, read your notes back. At which round did the lemon fade? What's left of your perfume, and does it match the base notes listed for it?

Both English articles put citrus at the top, and the French article's example puts vanilla in the base, so your kitchen strips let you check that order with your own nose. For more drills with blotters and spices, see the Class on training your nose, from smelling strips to nose fatigue.