What the Nose Knows: The Science of Scent in Everyday Life (2 page)

There is no place on the wheel for the wine critic’s gaseous adjectives. You will find “orange blossom” and “black olive” and the less flattering “soapy” and “cooked cabbage.” But you will not find “an impertinent little Pinot Noir” or a “flabby, overripe Cabernet Franc,” à la Miles Raymond. These free-form prose poems say more about a wine lover’s pretensions than about the character of the wine. To use the wheel, all you need is a glass and grocery store.

A
PRACTICAL SMELL
classification for beer was created in the 1970s by a Danish flavor chemist named Morten Meilgaard. His Beer Flavor Wheel has now been adopted worldwide. It uses fourteen categories and forty-four sensory terms to describe the smell and taste of any style of beer—lager, ale, or stout. Most of the descriptors deal with aroma; others involve taste (bitter for hops; sweet for malt) and sensory factors like carbonation. Meilgaard’s system includes reference standards, but unlike Noble’s wine wheel (which was inspired by it), one needs access to pure chemicals to create them. For example, to mimic the “papery” aroma of oxidized beer, one doses a pitcher of beer with
trans
-2-nonenal.

A brewer’s best friend is his nose. Desirable aromas tell him when the product is on target. By identifying off-smells in the product, a brewer can correct problems in the brewing process. For example, the smell of wet newspaper indicates that a beer has oxidized. Sunlight-damaged beer has a skunky smell. (Many years ago, Corona beer from Mexico was poorly made and oxidized easily. The acid in a slice of lime was an effective way to chemically neutralize the off-odor. Today Corona is made as well as any beer in the world, but the lime tradition lives on.)

Meilgaard’s beer system is less satisfying for the lay drinker than the Wine Aroma Wheel. Because the reference standards are made with single chemicals, they can be prepared with great precision. However, they don’t reproduce complex aromas like raspberry or asparagus, and they are not cheap and easy for the amateur beer enthusiast to make at home. An added frustration is that the descriptive terms for beer are confusing. In the “sulfury” category, for example, are “sulfury,” “sulfitic,” and “sulfidic,” terms only a chemist could love.

T
HE APPEAL OF
aroma wheels is that they organize product-specific smells into a few, easily recognized categories. As a result, food lobbies around the world have come up with their own versions. There is a chocolate aroma wheel from Switzerland and a Flavour Wheel for Maple Products, courtesy of Canada. There is a pan-European wheel for Unifloral Honey, and another for cheese (although with seventy-five different aromas it doesn’t really simplify things for cheese fans). There is a South African brandy wheel, and the Berkeley-based perfumer Mandy Aftel has created a Natural Perfume Wheel. Recently, some guys in the Philadelphia Water Department came up with a wheel for identifying the odors found in sewage. (Anyone who’s lingered on the banks of the Schuylkill River knows that wastewater offers a particularly rich olfactory experience.) The world has gone wheel crazy, and we can expect to see more of them in the future.

The Perfumer’s Problem

Odor space is an imaginary mathematical realm containing all possible odors. The aromas of wine and beer occupy only a small fraction of odor space—not nearly the full range of smells detectable by the human nose. Can smell classification work on a larger scale? Perfumes and colognes take up a bigger chunk of odor space: There are at least 1,000 currently on the market, with new ones added at a rate of about two hundred per year. Each has anywhere from 50 to 250 ingredients. If anyone has a lot of smells to keep track of, it is the perfumers who create them.

At its core, the practice of perfumery hasn’t changed much since it came to full flower in Renaissance Italy. In those days there were no more than 200 commonly available ingredients, all derived from natural sources, either botanical (essential oils, gums, spices, and barks) or animal (musk and civet). By the late nineteenth century, discoveries in organic and synthetic chemistry created a host of new materials. Some were novel, man-made molecules; others were pure chemicals isolated from the complex mixtures found in nature. The result is that the modern perfumer’s palette is far larger than his predecessor’s. Learning these materials is a correspondingly bigger task. How does a perfumer keep it all straight?

The professional perfumers Robert Calkin and Stephan Jellinek explain: “The novice perfumer may well feel daunted by the hundreds of bottles containing strange and often unpleasant smelling materials that line the laboratory shelves. But for the talented student the task of learning to identify them is in fact less difficult than it may seem at first.” The trick, according to these experts, lies in honing specific cognitive skills, namely learning new mental categories and how to fit new smells into them. To become a perfumer you don’t learn to smell like one—you learn to think like one.

The first step in training is to learn the smell of the available ingredients. The leading teaching technique—the Givaudan method, created by the French perfumer Jean Carles—introduces students to the major ingredients using a matrix approach. Imagine a grid of rows and columns. Each row is a fragrance family: citrus, woody, spicy, and so on. Each column is a training session. In the first session, students smell column-wise one material from each family: lemon oil, sandalwood oil, and clove bud oil, for example. In the second session, the students smell new examples: bergamot oil, cedarwood oil, and cinnamon bark oil. This process continues for about nine lessons, by which time the students are familiar with the olfactory differences between families. Now comes the hard part—learning the “contrasts” within a family. Each subsequent session traverses one row of the matrix. In the citrus lesson, for example, students smell lemon, bergamot, tangerine, mandarin orange, blood orange, grapefruit, and lime. The goal, according to master perfumer and teacher René Morgenthaler, is for the student to create a personal impression of each ingredient. These individualized mental hooks are the key to remembering the fine discriminations needed to do perfumery. The graduate of nasal boot camp must recognize more than 100 natural materials and around 150 synthetics. The professional perfumer eventually becomes familiar with every material in his company’s library—anywhere from 500 to 2,000 items—and is able to recognize every grade of each.

With the basic raw materials in mind, a trainee next learns to think like a perfumer. When a professional analyzes a fragrance or creates a new one, he does not think in terms of individual ingredients; he thinks of typical combinations called accords. An accord is a mixture of raw materials (rarely more than fifteen) that go together particularly well. Accords are the building blocks of perfumery. By combining several of them, the perfumer creates an initial sketch of the perfume, sometimes called a skeleton. In a way, creating a perfume is like writing software: a programmer starts with building-block software modules that already contain many lines of code. A computer program is built with many modules, just as a fragrance is assembled from accords. The analogy goes further—software is tested with iterative debugging; perfume is tested with repeated sniffing and tweaking of the formula.

An art form as subjective and personal as perfumery might be expected to resist computerization. In fact, the opposite is true. The practice of perfumery quickly adapted to the digital world in terms of tracking materials and recording formulas. At a more fundamental level, the perfumer and the software programmer share a similar mind-set that involves the logic of subprograms and modules. Some of the memory burden of those thousands of ingredients is relieved by computer technology. Perfumers browse the company’s entire inventory of materials on-screen. They assemble a formula with a series of mouse clicks. They save everything: formulas, failed trials, and favorite accords. Software is an active partner in the creative process. It warns the user when two chemically incompatible materials have been selected, thereby avoiding a formula that discolors when exposed to sunlight. Most important, it continuously tallies the cost of the formula and displays it on-screen as dollars per pound of fragrance oil. No matter how great the creative latitude on a given project, a perfumer always works to a dollar limit.

Once a novice starts to think like a perfumer, he begins to develop a new way of smelling. Individual ingredients recede and whole fragrances emerge: he learns to smell the forest before the trees. Given a new men’s cologne, he quickly recognizes it as, say, a Fougere type. Next he sniffs for the individual notes that define the Fougere pattern: lavender, patchouli, oakmoss, and coumarin. After confirming these, he smells further, looking for a new twist or nuance that sets this formula apart from all the other Fougeres in the world.

Perfumers reduce the complexity of their world to a small, manageable number of fragrance families. They use well-known accords to simplify the process of scent creation. The perfumer’s job is more about pattern recognition than about raw memorization; his mental map is uncluttered by free-floating details. Like most highly creative people, perfumers tend to be a little crazy; but they are not driven crazy from remembering thousands of smells.

The Shopper’s Problem

Hundreds of perfumes are available for sniffing in department stores and boutiques. They range in style from restrained elegance to loud assertion, from distinctive originals to blatant knock-offs. How does one shop for scent amid this sensory overload? Lacking the perfumer’s trained thought processes, the average person is completely at sea.

Fragrance houses—the companies that employ perfumers and create the juice for the Calvin Kleins and Cotys of the world—find it useful to organize perfumes by smell. The Haarmann & Reimer company published a fragrance genealogy that traces every style of perfume from its first appearance to the present day. It’s a nasal Book of Genesis: In the beginning was
Jicky
(Guerlain, 1898), and
Jicky
begat
Emeraude
(Coty, 1921), and
Emeraude
begat
Shalimar
(Guerlain, 1925), and so on through
Obsession
(Calvin Klein, 1985) and those that followed it. (Although some ancestral scents are well-known classics, it is sobering to see all the brand names that meant so much in their time but so little today:
Moon Drops
(Revlon, 1970),
Touché
(Jovan, 1980), or
Aspen
(Quintessence, 1990). Genealogies provide a sense of history, but they don’t help one to shop in the here and now.

Another style of perfume guide lists each brand by fragrance family: florals, aldehydics, chypres, and so on. This isn’t much help if you don’t know what a chypre smells like. (The term covers a range of styles having in common a warm, woody character with an animal-like undertone.) If you like Estée Lauder’s
Pleasures,
you can look up a dozen similar scents. What you won’t find is a measure of how similar they smell. Nor will you find the exact ways they differ from
Pleasures
—are they stronger, spicier, greener, muskier?

Most people don’t consult a reference book before shopping. They simply head for the department store. But once inside, things don’t get easier. Each fragrance brand has its own counter, attended by its own salesperson who will show you only the perfumes she is paid to show. If your ideal scent is one counter away, it might as well be in a different universe. Sephora stores broke with retail tradition by introducing the “open sell.” Brands are arranged alphabetically on the shelf, from Alan Cummings to Yves Saint Laurent. With no vested interest in any one brand, the Sephora staff is just as happy to sell you Alan as Yves. To introduce sensory logic to their store designs, the company has tried arranging perfumes by fragrance family: orientals here, florals over there. This may be the start of a badly needed rethinking of the retail experience.

Charts and guides, even those based on expert opinion, are still arbitrary views of odor space. They present the world according to one fragrance house, or more likely just its chief perfumer. No single classification has emerged thus far as the industry standard. If one did, it still wouldn’t help the average shopper, because perfumers don’t think like the rest of us. The professional detects rose de mai Bulgarian where the consumer smells flowers. The professional finds clear-cut differences among perfumes that strike most people as indistinguishably fruity-floral. What the average person needs is a map on which brands are arranged by how they smell to other average people.

P
ERFUME MAKERS
speak to the consumer with two voices: Ingredient Voice and Imagery Voice. Here is a classic example of the Ingredient Voice, from a description of Estée Lauder’s best-seller
Beautiful
(1985):

Vibrantly feminine floralcy of rose, lily, tuberose, marigold, muguet, jasmine, ylang, cassis and carnation accented with fresh mandarin and bright fruity notes. Warm background accord of orris, sandalwood, vetiver, moss and amber.