Scent over time

January 04, 2009 at 12:00 PM in: smell, time, music, perfume

One of the more intriguing aspects of perfumery is the evolution of scent over time. The more volatile components of a mixture ("top notes") predominate at first, and as they evaporate off they give way to the slower and heavier components of the scent ("base notes").

I'm very new to perfumes, but so far I am finding myself fascinated by the complexity of the initial scents and bored by the long and relatively simple finishes. For example, Christopher Brosius describes his Violet Empire: "the violet scent perpetually peeps out from behind a shining green veil." Indeed, out of the bottle it smells fantastic. On skin, the shining green veil soon dissipates and what remains seems floral and cloying, though a better nose than mine describes the finish as "deep woods and a mild trail of leather".

Contrast this with the development of a piece of music - many pieces start with a simple exposition of a theme, slowly building in complexity as the vocabulary gets established. This is most obvious in a Hindustani classical performance, which begins by slowly exploring the intervals of a raga within a single octave, juxtaposing only a few notes at a time and letting them fade before sounding new ones. Gradually the surrounding octaves are added to the mixture, and the soloist accelerates until many tones are ringing at once. It might take ten minutes before any rhythm is introduced, and another twenty before the fireworks really get going.

A perfume seems more like a single stroke of a gong - rich and complex when first struck, but settling down to a persistent hum. But while a gong lasts a few minutes at most, the base notes of a perfume persist for hours.

Wine tasting allows another approach - you get to take that journey from start to finish on each sip, as well as noticing the slower changes over the course of several glasses. However, wines have a much more constrained palette than what the perfumers work with.

The slowest change in scent I've ever observed took years, and was probably a chemical change rather than the gradual evaporation of volatiles. I picked a flower in Marin county - something like Artemisia Californica, but with perfect small silver-gold everlasting flowers. The sage smell lasted for months, fading to a distinct smell of maple syrup. After two years the maple scent was replaced by an increasingly powerful whiff of dried urine. It took a while to figure out where the odor was coming from, but I regretfully got rid of the flower.

Turin, Sanchez, Burr, and Gilbert

December 17, 2008 at 12:00 PM in: smell, perfume

Maybe I'm just late to the party, but the current interest in scent seems to trace back to a single individual: Luca Turin.  It started when Turin and Tania Sanchez wrote a book of inscrutable but hilarious perfume reviews. Chandler Burr then wrote a book about Turin and Turin's controversial theory about the mechanism of smell, and parlayed that into a job as the first ever perfume critic for the New York Times.

In response, Avery Gilbert wrote a less than complimentary review (pdf) of Burr's book and Turin's science, which led to a full-length book about the science of smell. Gilbert is occasionally pedantic - there are twelve pages devoted to debunking Proust and his fans. But What the Nose Knows is - title notwithstanding - the best popular science book on scent that I've read so far, if you're interested in the experimental evidence anyway.

Now, a fast-food chain is running a viral marketing campaign using perfume as the hook, and Dr. Gilbert has taken the opportunity to write a snarky Burr/Turin/Sanchez style review of Eau de Hamburger. Excerpt:

Flame's topnote unfolds like a prepubescent Asian contortionist climbing out of a crate of overripe Algerian pears. The bold viande accord in the heart introduces itself with solid, yet suave confidence - it's Richard Gere on steroids. Boisdur delivers a signature touch wtih a trace of instantly recognizable isopropylparabenzyldicaproic acetate. The effect is stunning: like spare ribs slow-cooking on a Weber E-210 at a Section C tailgate party in the Meadowlands. The drydown is long and satisfying.

Fifteen years ago the only book I found on smell was Max Lake's somewhat lascivious Scents and Sensuality, which was interesting but not exactly confidence-inspiring. Good times for olfactory aficionados - thank you Dr. Turin.