"The core of the seen and unseen universe smiles, but remember smiles come best from those who weep. Lightning, then the rain-laughter". - Rumi

Just in time for the much-delayed school year in British Columbia - the rainy season is upon us. Most Vancouverites don't welcome this type of change in weather, but I do. In places plagued with drought, such as my other homeland, the first rain signifies not only the changing season, but also determines the well-being of crops, and predictions for precipitation in the year to come.

In Hebrew, there is a special word for the first rain - "Yoreh". It has a special smell, and an air of excitement about it as Jews welcome the new year and begin the fall harvest season. Many stories have been told about tzadikim (sages or saints) that have saved the country from drought with vigils, fasting and prayers for rain.

In my many years of providing customized fragrance creations and matching scents to personalities, I've received countless emails describing people's faourite scents. The smell of the first rain in all its many permutations is one that comes up most frequently: rain on hot pavement, thunderstorm, wet earth after rain, in other words - petrichor...

The word was coined in 1964 and comes from the Greek petros (stone) and ichos (the liquid that flows in the gods' veins). It's exact definition accodring to the online Wiktionary is "the distinctive scent which accompanies the first rain after a long warm dry spell".

The main reason for the appearance of petrichor is a molecule called Geosmin, a metabolite of bacteria that lives at the top layer of the soil. You might also detect a bit of it in raw, unpeeled beetroot. Combined with the unique flora of the place graced with rain, the scent will have nuances of various roots and dried plant matter. This is why the scent each person associates with petrichor is unique to their homeland.

When I first moved to Vancouver, nearly 16 years ago, the only thing I missed more than my family and friends was the scent of the first rain in autumn, falling on the thirsty dry earth. It’s a scent one can’t describe to someone who never experienced it. And the occurrence of dry earth in British Columbia is a rarity. The closest I was ever able to explain it is that it is wet, musty, dusty and fresh.

The scent of spikenard essential oil comes very close to this (although the whole sensation of the clean air and the wetness is lacking from the experience of sniffing an oil from a bottle, rather than the outdoors). In 2001 I tried to capture that scent, and the result smelled ironically of the Pacific rainforest after the rain instead. The rainforests rarely go dry, but have a constant mysterious wet fresh smell about them, a mingling of all the conifers, moss, lichen and dead leaves rotting on the ground. The forest earth itself in fact layers of compacted woodchips, conifer needles and rotten leaves, which might explain why it does not quite smell like petrichor... So I decided to name it Rainforest instead.

Aside from spikenard, other natural raw materials that might remotely resemble petrichor are attar mitti - a baked earth attar that is produced from fragments of clay pots, distilled into sandalwood oil; and patchouli, with its dry, earthy, musty aroma.

Perfumes that have a distinctive petrichor or geosmin-like notes are Forest Walk by Sonoma Scent Studio, Demeter's Dirt and Neil Morris' Dark Earth.

How would you describe the smell of the first rain? Do you have any favourite perfumes that have that note?