Gulp: Adventures on the Alimentary Canal (2 page)

The early anatomists had that curiosity in spades. They entered the human form like an unexplored continent. Parts were named like elements of geography: the isthmus of the thyroid, the isles of the pancreas, the straits and inlets of the pelvis. The digestive tract was for centuries known as the alimentary canal. How lovely to picture one’s dinner making its way down a tranquil, winding waterway, digestion and excretion no more upsetting or off-putting than a cruise along the Rhine. It’s this mood, these sentiments—the excitement of exploration and the surprises and delights of travel to foreign locales—that I hope to inspire with this book.

It may take some doing. The prevailing attitude is one of disgust. There are people, anorexics, so repulsed by the thought of their food inside them that they cannot bring themselves to eat. In Brahmin Hindu tradition, saliva is so potent a ritual pollutant that a drop of one’s own spittle on the lips is a kind of defilement. I remember, for my last book, talking to the public-affairs staff who choose what to stream on NASA TV. The cameras are often parked on the comings and goings of Mission Control. If someone spots a staffer eating lunch at his desk, the camera is quickly repositioned. In a restaurant setting, conviviality distracts us from the biological reality of nutrient intake and oral processing. But a man alone with a sandwich appears as what he is: an organism satisfying a need. As with other bodily imperatives, we’d rather not be watched. Feeding, and even more so its unsavory correlates, are as much taboos as mating and death.

The taboos have worked in my favor. The alimentary recesses hide a lode of unusual stories, mostly unmined. Authors have profiled the brain, the heart, the eyes, the skin, the penis and the female geography, even the hair,
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but never the gut. The pie hole and the feed chute are mine.

Like a bite of something yummy, you will begin at one end and make your way to the other. Though this is not a practical health book, your more pressing alimentary curiosities will be addressed. And some less pressing. Could thorough chewing lower the national debt? If saliva is full of bacteria, why do animals lick their wounds? Why don’t suicide bombers smuggle bombs in their rectums? Why don’t stomachs digest themselves? Why is crunchy food so appealing? Can constipation kill you? Did it kill Elvis?

You will occasionally not believe me, but my aim is not to disgust. I have tried, in my way, to exercise restraint. I am aware of the website www.poopreport.com, but I did not visit. When I stumbled on the paper “Fecal Odor of Sick Hedgehogs Mediates Olfactory Attraction of the Tick” in the references of another paper, I resisted the urge to order a copy. I don’t want you to say, “This is gross.” I want you to say, “I thought this would be gross, but it’s really interesting.” Okay, and maybe a little gross.

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Similar products exist to this day, under names like “Dual Sex Human Torso with Detachable Head” and “Deluxe 16-Part Human Torso,” adding an illicit serial-killer, sex-crime thrill to educational supply catalogues.

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In reality, guts are more stew than meat counter, a fact that went underappreciated for centuries. So great was the Victorian taste for order that displaced organs constituted a medical diagnosis. Doctors had been misled not by plastic models, but by cadavers and surgical patients—whose organs ride higher because the body is horizontal. The debut of X-rays, for which patients sit up and guts slosh downward, spawned a fad for surgery on “dropped organs”—hundreds of body parts needlessly hitched up and sewn in place.

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The Hair
, by Charles Henri Leonard, published in 1879. It was from Leonard that I learned of a framed display of presidential hair, currently residing in the National Museum of American History and featuring snippets from the first fourteen presidents, including a coarse, yellow-gray, “somewhat peculiar” lock from John Quincy Adams. Leonard, himself moderately peculiar, calculated that “a single head of hair of average growth and luxuriousness in any audience of two hundred people will hold supported that entire audience” and, I would add, render an evening at the theater so much the more memorable.

1

Nose Job

TASTING HAS LITTLE TO DO WITH TASTE

T
HE SENSORY ANALYST
rides a Harley. There are surely many things she enjoys about traveling by motorcycle, but the one Sue Langstaff mentions to me is the way the air, the great and odorous out-of-doors, is shoved into her nose. It’s a big, lasting passive sniff.
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This is why dogs stick their heads out the car window. It’s not for the feeling of the wind in their hair. When you have a nose like a dog has, or Sue Langstaff, you take in the sights by smell. Here is California’s Highway 29 between Napa and St. Helena, through Langstaff’s nose: cut grass, diesel from the Wine Train locomotive, sulfur being sprayed on grapes, garlic from Bottega Ristorante, rotting vegetation from low tide on the Napa River, toasting oak from the Demptos cooperage, hydrogen sulfide from the Calistoga mineral baths, grilling meat and onions from Gott’s drive-in, alcohol evaporating off the open fermenters at Whitehall Lane Winery, dirt from a vineyard tiller, smoking meats at Mustards Grill, manure, hay.

Tasting—in the sense of “wine-tasting” and of what Sue Langstaff does when she evaluates a product—is mostly smelling. The exact verb would be
flavoring
, if that could be a verb in the same way
tasting
and
smelling
are. Flavor is a combination of taste (sensory input from the surface of the tongue) and smell, but mostly it’s the latter. Humans perceive five tastes—sweet, bitter, salty, sour, and umami (brothy)—and an almost infinite number of smells. Eighty to ninety percent of the sensory experience of eating is olfaction. Langstaff could throw away her tongue and still do a reasonable facsimile of her job.

Her job. It is a kind of sensory forensics. “People come to me and say, ‘My wine stinks. What happened?’” Langstaff can read the stink. Off-flavors—or “defects,” in the professional’s parlance—are clues to what went wrong. An olive oil with a flavor of straw or hay suggests a problem with desiccated olives. A beer with a “hospital” smell is an indication that the brewer may have used chlorinated water, even just to rinse the equipment. The wine flavors “leather” and “horse sweat” are tells for the spoilage yeast
Brettanomyces
.

The nose is a fleshly gas chromatograph. As you chew food or hold wine in the warmth of your mouth, aromatic gases are set free. As you exhale, these “volatiles” waft up through the posterior nares—the internal nostrils
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at the back of the mouth—and connect with olfactory receptors in the upper reaches of the nasal cavity. (The technical name for this internal smelling is retronasal olfaction. The more familiar sniffing of aromas through the external nostrils is called orthonasal olfaction.) The information is passed on to the brain, which scans for a match. What sets a professional nose apart from an everyday nose is not so much its sensitivity to the many aromas in a food or drink, but the ability to tease them apart and identify them.

Like this: “Dried cherries. Molasses—blackstrap.” Langstaff is sniffing a strong, dark ale called Noel. We are at Beer Revolution, an amply stocked, mildly skunky
^†
bar in Oakland, California, where I have an office (in the city, not the bar) and Langstaff has a parent in the hospital. She could use a drink, and we have four. For demonstration purposes.

In general, Langstaff isn’t a talky person. Her sentences present in low, unhurried tones without italics or exclamation points. The question “Which beer do you want, Mary?” went down at the end. When she puts her nose to a glass, though, something switches on. She sits straighter and her words come out faster, lit by interest and focus. “It smells like a campfire to me also. Smokey, like wood, charred wood. Like a cedar chest, like a cigar, tobacco, dark things, smoking jackets.” She sips from the glass. “Now I’m getting the chocolate in the mouth. Caramel, cocoa nibs . . .”

I sniff the ale. I sip it, push it around my mouth, draw blanks. I can tell it’s intense and complex, but I don’t recognize any of the components of what I’m experiencing. Why can’t I do this? Why is it so hard to find words for flavors and smells? For one thing, smell, unlike our other senses, isn’t consciously processed. The input goes straight to the emotion and memory centers. Langstaff’s first impression of a scent or flavor may be a flash of color, an image, a sense of warm or cool, rather than a word. Smoking jackets in a glass of Noel, Christmas trees in a hoppy, resinous India pale ale.

It’s this too: Humans are better equipped for sight than for smell. We process visual input ten times faster than olfactory. Visual and cognitive cues handily trump olfactory ones, a fact famously demonstrated in a 2001 collaboration between a sensory scientist and a team of oenologists (wine scientists) at the University of Bordeaux in Talence, France. Fifty-four oenology students were asked to use standard wine-flavor descriptors to describe a red wine and a white wine. In a second round of tasting, the same white wine was paired with a “red,” which was actually the same white wine yet again but secretly colored red. (Tests were run to make sure the red coloring didn’t affect the flavor.) In describing the red-colored white wine, the students dropped the white wine terms they’d used in the first round in favor of red wine descriptors. “Because of the visual information,” the authors wrote, “the tasters discounted the olfactory information.” They believed they were tasting red wine.

Verbal facility with smells and flavors doesn’t come naturally. As babies, we learn to talk by naming what we see. “Baby points to a lamp, mother says, ‘Yes, a lamp,’” says Johan Lundström, a biological psychologist with the Monell Chemical Senses Center in Philadelphia. “Baby smells an odor, mother says nothing.” All our lives, we communicate through visuals. No one, with a possible exception made for Sue Langstaff, would say, “Go left at the smell of simmering hotdogs.”

“In our society, it’s important to know colors,” Langstaff says over a rising happy-hour din. We need to know the difference between a green light and a red light. It’s not so important to know the difference between bitter and sour, skunky and yeasty, tarry and burnt. “Who cares. They’re both terrible.
Ew.
But if you’re a brewer, it’s extremely important.” Brewers and vintners learn by exposure, gradually honing their focus and deepening their awareness. By sniffing and contrasting batches and ingredients, they learn to speak a language of flavor. “It’s like listening to an orchestra,” Langstaff says. At first you hear the entire sound, but with time and concentration you learn to break it down, to hear the bassoon, the oboe, the strings.
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As with music, some people seem born to it. Maybe they have more olfactory receptors or their brain is wired differently, maybe both. Langstaff liked to sniff her parents’ leather goods as a small child. “Purses, briefcases, shoes,” she says. “I was a weird kid.” My wallet is on the table, and without thinking, I stick it under her nose. “Yeah, nice,” she says, though I don’t see her sniff. The performing-chimp aspect of the work gets tiresome.

While not discounting genetic differences, Langstaff believes sensory analysis is mainly a matter of practice. Amateurs and novices can learn via kits, such as Le Nez du Vin, made up of many tiny bottles of reference molecules: isolated samples of the chemicals that make up the natural flavors.

A quick word about chemicals and flavors. All flavors in nature are chemicals. That’s what food is. Organic, vine-ripened, processed and unprocessed, vegetable and animal, all of it chemicals. The characteristic aroma of fresh pineapple? Ethyl 3-(methylthio)propanoate, with a supporting cast of lactones, hydrocarbons, and aldehydes. The delicate essence of just-sliced cucumber? 2
E
,6
Z
-Nonadienal. The telltale perfume of the ripe Bartlett pear? Alkyl (2
E
,4
Z
)-2,4-decadienoates.