The Petrichor Note in Perfumery
The term “petrichor” refers to the characteristic smell of the earth after rain. It is a complex phenomenon that gives off a fresh, earthy smell often associated with nature. How is petrichor created? How do perfumers showcase this smell? Master Parfums tells you everything!
What Is Petrichor?
The term “petrichor” was coined in 1964 by Isabel Joy Bear and Richard Grenfell Thomas, both Australian mineralogists. They combined the Greek words “petra,” meaning stone, and “ichor,” corresponding to the blood of the gods in Greek mythology. The term petrichor refers to the characteristic smell of the earth after rain. It is a combination of volatile organic compounds released by plants, bacteria and fungi when they are wetted by rain striking the dry ground.
Petrichor refers to several elements:
Plant Oil
The first concerns the oily liquid secreted by plants, which helps protect the seeds and roots of plants by coating them. Indeed, thanks to this plant oil, plants reinforce their natural defences and better withstand periods of drought. This liquid is absorbed by the soil, and during the thermal shock of the cool raindrop falling on the dry, warm ground, a reaction occurs.
Geosmin
The second phenomenon concerns geosmin, a volatile molecule produced by soil bacteria, the actinomycetes, when they reproduce. Humans can detect it at very low concentrations, which means that even a small amount of geosmin can give off a very strong smell.
It has a very particular smell, a bit like wet earth or freshly turned soil. Although some may find the smell of geosmin unpleasant, it is in fact very important for the environment. It plays an important role in regulating plant growth and in the nutrition of the animals that live in lakes and rivers.
When the oily plant liquid comes into contact with geosmin, the two smells can mingle to create a unique smell that is often described as very pleasant and soothing. This smell is often associated with freshness and nature.
Ozone
During thunderstorms, lightning produces ozone, which can remain in the air after the storm, giving the air a fresh, distinctive smell, charged with negative ions. These ions can combine with particles in the air to form aerosols. The combined petrichor molecules are thereby all the more carried through the humid air.
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Why Is Petrichor So Pleasant?
It would seem that very few people dislike petrichor. According to some anthropologists, this positive cognitive bias linked to petrichor may be related to our evolution. At the dawn of humanity, we depended on rain to ensure the growth of crops and the survival of the community. When rain fell, it was therefore often good news, and the smell of rain on dry ground could evoke feelings of relief and joy.
Moreover, in many cultures, rain is often seen as a symbol of fertility and renewal. The smell of petrichor can therefore also be associated with these positive ideas and be considered a sign of good omen.
Indeed, it is rain that enriches flora and fauna. It is therefore natural that our collective consciousness associates petrichor with positive events and interprets it as a pleasant smell.
The Petrichor Note in Perfumery
As we have seen, petrichor is the pleasant smell that rises from the earth after rain.
In perfumery, petrichor can be used to add a natural, earthy note to a perfume.
However, petrichor is not often used as is in perfumery, because it is difficult to capture this complex smell. Instead, perfumers often use synthetic ingredients to recreate the smell of petrichor. These ingredients can include notes of earth, moss, wood and foliage.
Petrichor can also be used as inspiration for creating perfumes that evoke rain and landscapes after a shower. These perfumes can include notes of fresh plants, wet flower petals, tea leaves and other ingredients that evoke a damp, refreshing atmosphere.
Petrichor can also be used as a base note or a subtle facet in a more complex perfume. It can add depth and an extra dimension to a perfume, especially when paired with other natural raw materials such as plant and flower essential oils.
In terms of olfactory family, petrichor is often described as having earthy, mineral, vegetal and musky notes. However, there is no specific olfactory family that corresponds exactly to the smell of petrichor.
In general, perfumes that contain earthy and mineral notes, such as perfumes of the chypre or woody families, can evoke certain nuances of petrichor.
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A Few Perfume References with the Petrichor Note
There are several perfumes that contain the petrichor note or draw inspiration from it. Here are a few examples:
- Petrichor Plains by Mihan Aromatics: This perfume, created by Josh Mihan and Jules Brown, draws inspiration from the smell of rain on the city, with notes of rain, iris, cardamom, earthy notes and asphalt.
- With When the Rain Stops by Maison Margiela, Fanny Bal evokes the smell of an ozonic rain—it is fresh, green, aqueous and earthy.
- Petrichor by Demeter Fragrance Library: This perfume, created by Christopher Brosius, captures the smell of the earth after rain, with notes of wet earth, green leaves and vetiver.
- Baie 19 by the house of Le Labo contains notes of fig leaves, juniper berries, pink pepper, black pepper, sandalwood and patchouli. Frank Voelkl creates here a fresh, herbaceous and slightly woody fragrance with a spicy touch. A fresh, damp effect of the earth after rain.
- La Pluie by Miller Harris, created by Lyn Harris, evokes the smell of rain in gardens, with notes of bergamot, violet leaves and cedar.
- After the Rain by the house of Solstice Scents, by Angela St. John. The perfume evokes the smell of wet leaves after a summer rain. The floral notes of lotus flower, lilac and violet add a touch of softness and femininity to the perfume, while the earthy notes give it depth.
- Obviously, one immediately thinks of Guerlain’s masterpiece, Après l’Ondée, created by the perfumer Jacques Guerlain; this perfume is a tribute to the light, romantic atmosphere that follows a shower. It is a soft, refreshing perfume that evokes the smell of nature after a summer rain.
These perfumes can vary considerably in terms of notes and intensity, but all seek to capture the essence of the smell of rain and petrichor.
Petrichor is an interesting and unique olfactory note that can be used in different ways in perfumery. Whether used as is or as inspiration, it adds a touch of nature and freshness to any fragrance.
