Love that fresh, musky earthy smell that permeates the air when the first monsoon rain hits the dry ground? A petrichor is known, a pleasant cocktail of fragrant chemical compounds, some produced by plants, others produced by bacteria that live in the soil.
These bacteria are the main contributors to the distinctive earthy odor. When they die during dry spells, they release a compound called geosmin to which the human nose is extremely sensitive. But geosmin cannot rise into the air until the first raindrops splash on the ground and push the geosmin molecules out of the ground.
While researchers are only just beginning to understand the chemistry behind this wonderful fragrance, a small town in Uttar Pradesh, India, has captured this scent in a bottle so that it can be worn on their clothing as a perfume for hundreds of years.
Kannauj is located on the banks of the Ganges River, between the cities of Agra and Lucknow. The ancient city has been the home of the perfume industry since the days of Harshavardhana, who ruled North India in the 7th century. Kannauj perfumes were famous among the Mughal emperors who ruled India for almost 300 years. Some 1,300 years later, nearly half of Kannauj's 1.5 million residents are still involved in making fragrances using traditional methods.
Each morning, local farmers pick a variety of flowers such as rose, jasmine, champaca, lotus, ginger lily, gardenia and dozens of others and deliver them to more than two hundred perfume distilleries that dot the city. The flowers are mixed with water and heated in large copper vats called degs. The aromatic vapor is transferred through bamboo tubes to a container containing sandalwood oil that acts as the base of the attar or perfume. The perfume is then transferred to camel skin bottles whose porosity allows excess water to evaporate, trapping the fragrance and oil inside.
Kannauj's most notable product is mitti attar, or "perfume of the earth." The mitti attar making process is similar to any other scent compound, but instead of flower petals, the degs are filled with flat bricks of dry earth, a jet of water from the nearby pond, and then the vats are sealed with clay. It takes six to seven hours before all of the aroma evaporates from the clay.