How to Make Sense of Scents
Can language ever capture the mysterious world of smells?
My obsession with perfume began when I was around ten years old, spritzing on layer after layer of my mother’s Anaïs Anaïs and Poison, until I reeked of a duty-free store. It continued through my mall-rat teen-age years, when I blew through my babysitting tips at Bath & Body Works, convinced that I could amplify my personality with a generous dose of Sun-Ripened Raspberry. Throughout my twenties, I collected hundreds of fragrance samples, bought for less than five dollars apiece from Web sites with names like the Perfumed Court and Surrender to Chance. Tiny glass vials of liquid tuberose regularly spilled out of my coat pockets. So when an editor at a newspaper for which I occasionally wrote about hair and beauty trends asked me if I had anything to say about perfume, I told her I did. I assumed that the main requisite for the task was personal experience, not technical expertise; surely I already had the vocabulary for detailing the scentscapes I’d been wandering for years. I knew I loved the smell of violets—their chalky, chocolate undertones. Or I thought I knew. Sitting down at my keyboard, I began to waver. Was it more like talcum powder and linden honey? Or like a Barbie-doll head sprinkled with lemonade?
Talking about smells can feel a little like talking about dreams—often tedious, rarely satisfying. The olfactory world is more private than we may think: even when we share space, such as a particularly ripe subway car, one commuter may describe eau d’armpit as sweet Gorgonzola cheese, another will detect rotting pumpkin, and a third a barnyardy, cayenne tang. What surprised me is that using phrases like “barnyardy, cayenne tang” is a perfectly valid, even preferred, way to write about nasal experiences. Many of the most seasoned perfume critics incline toward the rhapsodic, as do the would-be critics who gather on the Internet to wax eloquent about the things they’ve smelled. One of my favorite hubs for odor aficionados, the Web site Fragrantica, an online “perfume encyclopedia” that launched in 2007, has the feel of a cacophonous bazaar: on its message boards, users swap perfumed prose back and forth, racking up hundreds of new posts each day.
On Fragrantica’s page for Violette, a violet soliflore (the industry term for a perfume that attempts to replicate the scent of a single flower) from the French house Molinard, you will find little consensus and lots of enthusiasm: “reminds me of sweet tarts from my childhood”; “This is a dance of fairies, in the deep of a forest where all is about light and shadows”; “a twilight summer sky, a glaring garland of bare incandescent bulbs, larded fruit pies, some musk from the crowd”; “my 5 year old son told me it smells disgusting, like ‘something dead.’ ” The desperate maximalism of these adjective pileups has a kind of poignancy. Smell—bodily and human yet invisible and heady—defies our expressive capacities in a way that other senses don’t. In our clumsy efforts at the ineffable, there is both passion and melancholy.
Would it help if we had a scientific lingua franca for talking about these aromatic adventures? There is chemistry, of course, which explains why certain essences smell like pinecones, or cotton candy. Violets, whether you detect a puff of cocoa or a hint of Barbie, get their enchanting sillage (or fragrance trail) from ionones, aromatic compounds that invade and numb the nasal passages in delicate waves, giving the flower a bizarre ability to flirt with the nostrils. If we all knew about indoles, the fetid natural compounds found in both jasmine blooms and human excrement, or sabinene, a terpene that gives both cedar and oregano their herbaceous punch, would we be better able to understand our shared airspace?
The impulse to taxonomize our elusive sensory experiences is not a new one. In the 1976 book “Wines: Their Sensory Evaluation,” Maynard Amerine, a fermentation expert, and Edward B. Roessler, a mathematician, took fellow wine connoisseurs—who rival Fragrantica users in their love of florid verbiage—to task, insisting that poetic evocations be accompanied by statistically replicable evaluations. They didn’t want to know what made a wine “angular” or “austere”; they wanted to understand what accounted for our perception of acidity. A similar desire for precision lies behind Harold McGee’s nearly seven-hundred-page new book, “Nose Dive: A Field Guide to the World’s Smells” (Penguin Press), the result of a ten-year quest to name and categorize every noticeable fragrance on earth.
Learning to detect specific scent notes “isn’t just an intellectual exercise,” McGee writes. It’s a full-body transformation. He cites the French sociologist Bruno Latour, who, in his 2004 essay “How to Talk About the Body,” mused about the way that perfumers in training learn to identify increasingly delicate and obscure essences over time: “It is not by accident that the person is called a ‘nose’ as if, through practice, she had acquired an organ that defined her ability to detect chemical and other differences.” A nose isn’t born; she’s made.
McGee, a food scientist in San Francisco, is especially interested in the playful pas de deux between the nose and the tongue. His 1984 book, “On Food and Cooking: The Science and Lore of the Kitchen,” popularized what became known as molecular gastronomy and earned him a mythological status among swaggering chefs who wanted to test the boundaries between stoves and Bunsen burners. The award-winning British chef Heston Blumenthal, best known for his offal innovations and porridge made with snails, once said that McGee’s tome “defined my unconventional approach to cooking. I wasn’t inquisitive before that.”
McGee’s immersion in what he calls the “osmocosm” (from the ancient Greek root for “odor”) began with the mystery of why certain unrelated foods mirror one another on the palate. He noticed that some Parmesan cheese tasted like pineapple, and that some oysters had the same vegetal crispness as raw cucumber. Other analogies were more far-fetched, but compelling: green tea could be oceanic, and some red wine had a distinct aftertaste of horse manure. “The flavor echoes I’d perceived,” he concluded, “are similarities specifically in smells.” McGee started by breaking down gastronomical odors, but soon expanded beyond the kitchen, documenting the smells of asteroids, asphalt, urine, wet earth, seaweed, sourdough, yogurt, dead animals, sassafras, and smoke—the “mundane yet revelatory things that fill our lives.”
This collision of the mundane and the revelatory makes McGee’s book as enjoyable to thumb through as the Fragrantica forums, though his guide is much better researched and far less baroque. It unfolds like a set of smart answers to essentially silly questions about quotidian life. Ever wonder why sweaty armpits stink? And, in the worst cases, why they stink of shallots in particular? McGee reports that the apocrine sweat glands, which kick into high gear during adolescence, do their best to hide the evidence of their own microbiomal bouquet. Sugars and amino acids bind to volatile, potentially rank molecules, thereby preventing the release of any foul smell. But when bacterial interlopers, such as bacillus and staphylococcus, break these bonds and “liberate” compounds like hydroxymethyl-hexanoic acid, then the full power of B.O. is unleashed: “rancid, animal, cumin-like.”
McGee’s tangled web of fragrance families starts to reveal fascinating relationships. By charting the genealogy of the piquant invaders of teen-age underarms, he discovers that they are the “very same molecules that scent goat and sheep meats, milks, cheeses, and wools.” This is no accident. Traditional cheese-makers cultivated their curds with a “sweat-like brine” for weeks. Once humans realized they could mimic their own bodily ripeness in their food, they simply couldn’t help themselves. “The smells of the human body may be socially embarrassing,” McGee writes, “but for children, and privately for adults, they’re often irresistible.”
The cozy relationships between natural secretions and savory foods, or accidental emissions and eros, are well known to anyone who has nuzzled the dirty scalp of a loved one, but McGee lays out the molecular evidence for these desires. We might like to think we are most drawn to lovely, “clean” smells—laundry, linden blossoms, a eucalyptus breeze—but more often than not our greatest sensory delight comes from our most intimate, and most odiferous, nooks and crannies.
It’s tempting to wonder how my perfume writing might have been different if I’d had “Nose Dive” on hand when I was starting out. In 2010, I puzzled over a new trend in “animalic” perfumes—unwashed, nocturnal scents with names like Ma Bête and Bat. (These were synthetic essences; fragrance-industry overseers now heavily regulate the use of many animal-derived products, such as castoreum, from beaver glands, and hardened whale feces known as ambergris.) At the time, I took a philosophical view: maybe these carnal scents evinced a longing for strangers’ bodily funk in an age of alienation.
McGee does not make such grand claims; he is more interested in analyzing the deep origin stories of smells than in tracking changeable cultural trends. Many of the molecules we smell today, he notes, have been around since the planet’s earliest days. Plenty of them are toxic—ammonia, say—but, even when dangerous, these primordial scents often have an intoxicating allure. “The smells of earth will always be our reference points,” McGee writes. “Lighter fluid or stove fuel, scorched oil, a vinegar dressing, a deviled egg, a just-unwrapped cheese, a sip of wine or rum: all offer distant echoes of the early cosmos.”
He is occasionally drawn to poetic diversions, citing research showing that petrichor, the sublime scent emitted when rain hits rocks or pavement, comes not from the minerals in the stone but from an imperceptible layer of “volatiles” covering all outdoor surfaces. These volatiles, generated by fungi, plants, and even human technology, are, McGee writes, “usually too sparse and omnipresent for us to notice them in the air around us.” It is only during a storm that what soil scientists call a “wet-up” can occur, and a fine mist of abundant life becomes perceptible to our noses. Rain reminds us of what is already there; it reattunes us to the ambient magnitude of the natural world. (Many perfumers have sought to bottle petrichor: one scent, inspired by a foggy hike in Northern Ireland, contains “ozonic and radiant materials.”) Our sense of smell has many functions: it’s a warning system, a taste enhancer, a pheromone alarm. But it is also an instrument for wonder, for noticing that which we often take for granted, and for which we rarely have a name.
In 2014, a Rockefeller University study claimed that the human nose, long thought to be inferior to dog or bear snouts, could isolate more than a trillion smells. The study, part of a burgeoning academic field called scent studies, did not stand up to review—it turned out there was a flaw in the mathematics—but it kicked off more research to determine the actual might of the human organ. In 2017, a neuroscientist at Rutgers University named John McGann published a provocative paper that, by comparing the olfactory bulbs of different animals, also seemed to suggest that we’re better smellers than we’ve gotten credit for. “We put the human bulb next to the mouse bulb and gasped,” he wrote. “It was gigantic.”
Scent studies were good for business, too. In recent years, the number of scented products for the home has exploded: where there was once just “lemon fresh” or “ocean breeze” dish soap, now there are hundreds of varieties, including “honeycrisp apple,” “sea salt neroli,” and “palmarosa wild mint.” One study predicted that the scented-candle business will net $4.22 billion by the end of 2024. You can now find candles that mimic the smells of Catholic Mass, a warm French baguette, a tomato vine in the hot sun, and a rotting bouquet inside a funeral home.
In “Smells: A Cultural History of Odours in Early Modern Times” (Polity), the French professor and historian Robert Muchembled is eager to note a cynical connection between the recent boom in the science of fragrance and the expanding scented marketplace. “The recent surge of interest in the human sense of smell is part of a vast cultural phenomenon whose underlying causes are deep-rooted, yet readily identifiable,” he writes. “You just have to follow the money.” Muchembled grumbles that the emphasis on novelty has overtaken a crucial aspect of understanding our nostrils—of how they adjust not only to molecules but also to changing societal mores.
Muchembled evokes the sensory world of Europe from the Renaissance to the early nineteenth century, a place and time that were extremely stinky. The streets of Grenoble, France, he writes, were stagnant cesspools of human and animal excrement, where “the hoi polloi were expected to let their betters walk on the higher side away from the gutter” to avoid being splashed with the repulsive muck. Human noses were always sensitive, but also highly adaptable. People in the Middle Ages did not think that roads lined with chicken droppings smelled pleasant; they simply got used to the stench. This phenomenon persists, as my colleague Charles Duhigg found while digging into the marketing of Febreze spray in his book “The Power of Habit.” The smell-masking product was initially marketed to smokers and people with pets, but nobody bought the stuff; people with “smelly” houses no longer noticed the smell. It was only by appealing to obsessive cleaners—people who didn’t actually need Febreze—that a wild best-seller was launched.
Febreze is hardly the first fashion to be born of our attempts to control the scentosphere. In smellier eras, certain professions took a large load of the olfactory burden: leather tanners, fishmongers, and fabric cutters (urine mixed with vinegar was a common color fixative for textiles). Creating a barrier between these trades and the general public led to fragrant innovations. Perfume became popular as a method of masking the curdled, meaty scent that emanated from leather goods. “Scented gloves,” Muchembled writes, “were the absolute height of high-society fashion in the reign of Louis XIII.”
And it wasn’t just the floral and the powdery that were in vogue. After a perfumer submerged a hide for gloves in a bath of orange-flower water, he would rub it with a mixture of ambergris, musk (glandular secretions from a deer), and civet (the perineal discharge of a bushy, mongoose-like mammal). French women, it seems, wanted their hands to smell at once like nature’s serenity and its monstrosity. The British, ascetics to their core, apparently found this practice distasteful; one Elizabethan playwright wrote, of kissing a lady’s glove, that “civet makes me sick.”
Smell can never truly be understood through science, Muchembled argues, because it is always vulnerable to the whims of popular taste. In sixteenth-century France, amid religious moralizing and the pervasive fear of witchcraft, the scent of a woman’s undercarriage, once considered an ambrosial ideal, became synonymous with the occult. The stigma was worse for aging women, who became seen as olfactory ogres; Muchembled quotes the poet Joachim du Bellay’s disgust at an “old woman older than the world / older yet than squalid filth.”
Our own experience confirms that smells are subject not just to major cultural changes but also to minor shifts in context: the same smell that greets you at the door of a cheesemonger has a very different effect when confronted at the door of a porta-potty. Where McGee seeks a common vocabulary for exploring the osmocosm, Muchembled reminds us that the variables of time and place may defy a truly shared language. What we smell depends on what’s in vogue and what’s valued—on what cultural forces happen to be swirling in the air.
In Muchembled’s telling, a radical turning point in our olfactive history arrived with the plague. When the disease swept across Europe, in the fourteenth century, the nose was regarded mainly as a kind of built-in weathervane for dangers; it rooted out rot, fire, and disease. The going assumption during the plague years—endorsed by authorities such as the French doctor Antoine Mizauld—was that the illness spread through putrid aromas, and that the best protection from the epidemic was to cloak yourself in prophylactic perfume. Mizauld’s preventive suggestions included carrying a pomander (a lemon, an orange, or a lime studded with cloves) or a handkerchief full of laurel leaves, soaked in cinnamon and rose water. He also recommended dabbing the eyes and nose with a spike of lavender oil and purifying the air inside the home by burning sweet-smelling substances such as benzoin, nutmeg, and myrrh on a bed of hot coals, often inside a small, bird-shaped container.
After the plague eventually passed, Muchembled theorizes, a new kind of mass euphoria set in when people were able to smell for pleasure again. After all the suffering and annihilation, the nostrils were allowed a sumptuous victory lap. This is the thinking that led Diderot, in the mid-eighteenth century, to write that the nose was the most “voluptuous” of the organs, turning our sensual antennae toward hedonism and delight.
These ideas hit differently today, as we face a virus that often spreads by way of our noses. In the first few weeks of lockdown, one of the eeriest developments was the discovery that many COVID-19 patients lost their sense of smell and taste. I found myself constantly huffing coffee beans and garlic cloves, just to insure that my schnoz was still functional. Now, after eleven months indoors, I am not even sure I know what my apartment really smells like. Like the dwellers of medieval Grenoble or Febreze’s mistaken targets, I’ve no doubt grown numb to my balmy bubble.
While we’ve lived in lockdown for the past year, daily encounters with surprising smells have dramatically diminished. The mask that I wear on walks filters out most of the odors of city life. I cannot remember the last time I was lured in, like a hapless Gretel, by the caramel allure of a Nuts 4 Nuts cart, or forced out of an elevator by a cloud of noxious gardenia, wishing a stranger had practiced more restraint. It takes effort to seek out novel aromas these days, and I’ve become increasingly madcap in my pursuits, ordering pickled beets, incense papers, and double-ginger tea just to shock my nose out of its stupor.
The stupor can be systemic. Some people with COVID-19 seem to have been afflicted with lasting anosmia—the loss of smell—and the effects go beyond missing the zest of a just-peeled orange or the salt of a sea breeze; they may report feeling depressed or adrift. Dr. Sandeep Robert Datta, a neurobiologist, recently told the Times that, while many think of scent as “an aesthetic bonus sense,” it is a vital link between people and their environment. Losing that link can be traumatic. “People’s sense of well-being declines,” Datta said. “It can be really jarring and disconcerting.” Perhaps anosmia feels so traumatic because smell is so personal, wrapped up with one’s own idiosyncratic narrative and memory. Spongy vanilla cake dunked in tea may have rocketed Marcel Proust backward into his pampered youth, but the whiff of madeleines will mean something entirely different—if it means anything—to you.
I’ve continued reading Fragrantica late into the night in my own little cloister, hoping that we will one day soon return to inhabiting a common scentscape. But I also have a new appreciation for the elusive quest to track down smells: while there is an undeniable appeal to pursuing a “proper language” for discussing the osmocosm, there is also something to be gained by accepting that much of the pleasure of nasal perception is untranslatable. When we are at last able to swoon together again, unmasked and unmoored, over lilacs or hot brioche, what we will really be sharing is secret reverie. ♦
