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Turin spent the most time with me at the counters of Chanel, Guerlain, and Estée Lauder, the last of which he said was underappreciated. He wanted to smell a new Lauder perfume: Jasmine White Moss. It is a classic chypre, the French word for “cypress” and the name of a famous 1917 perfume that blended sweet amber resin, citrus, and woody, oak-moss notes in what became an endlessly varied triad. The current classic of the genre is Chanel’s Cristalle. Turin pronounced the new Lauder “as good as it gets.” I smelled both Cristalle and Jasmine White Moss at length–the “heart” and the “drydown,” after 15 minutes to an hour, are what really matters–and found Cristalle to be admirably formal and cold, as Turin said I would. By contrast, Jasmine White Moss was startlingly sweet at first but was then reined in by the sterner oak moss and wood.

Turin likes chypres, but he’s fascinated by the “wonderfully spare aesthetic” of what he calls nouvelle parfumerie, which is characterized by dry wood, smoke, tar, and the abundant use of aromas that don’t exist in nature. Landmarks include Bertrand Duchaufour’s 2004 Timbuktu for L’Artisan Parfumeur and Comme des Garçons’ 2 Woman, “rasping and caressing,” designed in 1999 by ­Duchaufour’s colleague Mark Buxton. At Saks, Turin gave me a whiff of another fragrance he guesses is 80 percent synthetic–the same proportion he estimates in the Lauder, but this one designed to be new and strange: Rush, by Gucci. He loves it. “This creature may be from outer space,” says The Guide, “but its blood is warm.” I found it like a neon sign as bloody red as its box–impossibly strange, and frankly emetic.

it’s chemistry

How do chemists find these chemicals that mimic natural fragrances, enhance aromas, or smell completely new? By trial and error. Fragrance chemists can build the molecules that produce a smell, and then test variants. But they have never been able to design odorants without weeks or months of labor and expensive trials. Turin says he has found a way to do just that, guided by a different theory of how molecules stimulate smell perception. It is not his reviews, however brilliant, but The Secret of Scent (2006), describing the molecular-vibration theory of olfaction, that he hopes will be his legacy.

For decades the guiding theory was that a molecule’s shape determined smell: in lock-and-key fashion, a molecule would bind to a receptor site in the nose, ultimately sending signals to the brain that result in the experience of a smell. The lock-and-key model had proved widely applicable in biochemistry, and it seemed natural to extend it to olfaction, as Linus Pauling did in 1946. But 50 years of fragrance chemistry has shown little correlation between molecular shape and odor. Musks, for example, have very similar shapes and very different odors; tiny changes to the molecule of, say, an elusive floral fragrance can wreck its smell. Turin revived a theory, originated in the 1920s, that posited a correlation between molecular vibrations and smells. The English chemist Malcolm Dyson formally proposed it in 1938, and Robert H. Wright, a Canadian chemist and physicist, advanced it in a 1977 paper. But they both lacked an explanatory mechanism.

Any mechanism would have to explain how the nose can do the work of a spectrometer, without infrared beams to excite vibration. Since humans have only 347 smell receptors, a discovery announced in 1991 by Linda Buck and Richard Axel, each receptor must somehow recognize thousands of smells. In Turin’s theory, an odorant molecule that fits into a receptor’s binding site can switch on the receptor only if the molecule has a particular vibration, a quantum of energy matching the difference between two energy levels in the receptor. Once the sluiceway is open, electrons can travel through the molecule across the receptor, which recognizes the smell in much the way that cone cells in the retina recognize color by frequencies, or hair cells in the cochlea recognize sound vibrations.

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Credits: Mark Ostow

Tagged: Biomedicine

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