There is a town in India dedicated to capturing the scent of rain. For centuries, perfume-makers in Kannauj, an ancient village about 250 miles northwest of Delhi, have been distilling kiln-baked clay and sandalwood oil to create a precious elixir called mitti attar that smells like precipitation falling on dry soil. We all know this scent, the humid, vaguely metallic tang of moisture meeting earth at the beginning of a rainstorm that is as fleeting as it is highly specific. It’s called petrichor—a word derived from the Greek petra (stone) and ichor (the blood of the gods)—and I find it utterly magical. I have a tiny bottle of mitti attar from India that was given to me by a friend, and every time I sniff it, I feel as though I am simultaneously uncorking a memory and opening up a new world.
Evidently, I am not alone. As this long, hot summer has unspooled, online searches for petrichor fragrances have surged (94.4% since last year, according to market research platform Spate Data). People seem to be craving the scent of something cooling and quenching, an olfactive promise that less oppressive weather lies ahead. It may also be happening for the same reason that tomato-leaf fragrances are trending: Many of us are experiencing an urge to reconnect with the natural world, especially in ways that remind us of childhood.
“Everyone has memories of petrichor,” says Steven Gontarski, senior brand manager for niche fragrance retailer Luckyscent. “Summer vacation when you were a kid, or going on a road trip and getting caught in the rain. It’s nostalgic, and many of us are feeling a desire to go back to a more comforting time.” Along with an upswing in customer requests for fragrances featuring a petrichor note, Gontarski is also seeing an increased interest in perfumes that suggest the smell of mushrooms, oysters, and pollen. “It may be attributed to the ‘touch grass’ notion,” he says. “We get so wrapped up in the digital world that we lose sight of the fact that we’re actually mammals living on Earth. When I reach that point, I definitely have the desire to look at stars and smell the ground.”
The scent of petrichor is produced when microbes living in soil and rocks are released by the impact of raindrops, combined with the smell of organic compounds emitted by plants that are amplified by the presence of moisture. This reaction tends to happen when the earth is particularly parched, which is why you don’t smell petrichor every single time it rains, giving it an elusive quality that adds to its allure. Although the phenomenon was first identified in the late 1800s, it wasn’t until 1964 that Australian researchers Joy Bear and Richard Grenfell Thomas coined the word “petrichor” to describe it. The following year, scientists isolated geosmin, the specific molecule responsible for petrichor’s wet-earth smell, which is also found in raw beets, freshly dug soil, and clammy basements. The human nose is remarkably adept at smelling it; we can detect it in levels as low as a few parts per trillion.
The smell of petrichor is relatively new in perfumery, although there have been many beautiful olfactive meditations on the idea of rain over the years, including Guerlain’s iconic Après l’Ondée (which translates as “after the rain”), a powdery floral from 1906. The first synthetic geosmin note became commercially available in the early 2000s, and perfumers began to play with it to evoke a realistic sense of thunderstorms and rain-struck earth. However, geosmin is notoriously hard to work with as it can easily skew musty when used with too heavy a hand. Perfumers often opt to build a petrichor effect with other ingredients, using the grassy aroma of vetiver, the loamy smell of patchouli, or marine notes and aldehydes to elicit an impression of electricity-charged air and thirsty vegetation.
