All hot! All hot!
Pepper pot! Pepper pot!
Makes backs strong,
Makes lives long,
—Traditional Philadelphia street-vendor cry
“You come from far away,” the old man said, “where the devil left his jacket.” His speckled grey pony shifted beneath him, shaking the braided circlets of blue, red, and green leather that hung from its homespun bridle. I tried to meet the man’s eyes, but his stare never wavered from the air just above our heads. So I smiled at the horse, feeling foolish. They were blocking our path, but as visitors to a tribal area we needed permission to pass. The conversation didn’t seem to be going well.
“We’ve been mistreated ever since you came here,” he said, and I was confused. Hadn’t we just arrived? I wasn’t even sure if almendro grew in this forest. Then he clarified: “You and your Columbus.”
In biology, scouting new research sites occasionally involves sneaking a look at a promising field or forest without leave. But those few words reminded me that I was trespassing on an entire continent. Even the Costa Ricans with me didn’t count as locals—their ancestors came from Spain, following the trail blazed by Columbus himself when he dropped anchor at nearby Puerto Limón in 1502. Eventually, the old man nudged his pony to the side of the road and, having made his point, graciously gave us welcome. We didn’t find almendro that day and I never returned, but his words stayed with me. Centuries may have passed, but people still journey to the ends of the earth searching and seeking. And later I realized that Christopher Columbus and I did have one thing very much in common: we’d both come looking for seeds.
“Simply standing on the beaches,” the great explorer once wrote, “ . . . we find such traces and clues of spices that we have reason to believe much more will be found in time.” The logbook from his first voyage contains no fewer than 250 botanical descriptions, often-detailed accounts of the crops, trees, fruits, and flowers he encountered in the Caribbean. But while the list included plants (and seeds) that would redefine European cuisine and commerce, from corn to peanuts to tobacco, Columbus showed hints of disappointment as those first weeks wore on. “I am sorry to say I do not recognize them,” he wrote, after inspecting the herbs and shrubs of Isabella Island (now Crooked Island). Several days later, the flora made him “extremely sorry,” and in another passage he laments a forest of fragrant but unfamiliar trees: “It grieves me extremely that I cannot identify them.” Columbus felt worried, because while his ships may have bumped into a New World along the way, the admiral had promised his sponsors a much different outcome. Queen Isabella, King Ferdinand, and all of his other noble backers expected more than tales of discovery—they wanted to get rich. They had invested in a new trade route to Asia and expected a return paid in Asian products: gold, pearls, silk, and, above all else, the exotic spices that grew nowhere else. Unfortunately, neither Columbus nor anyone traveling with him had any idea what they looked like.
In the fifteenth century, spices reached Europe only after passing through so many intermediaries, along such a complex network of Asian and Arab trade routes, that people on the receiving end saw only the finished products, with little hint of how or where they grew. Popular myths suggested looking for flaming trees guarded by serpents, examining the sticks in Arabian bird nests, or harvesting twigs and berries from Paradise itself. Marco Polo, at least, attributed spices to real plants growing in real places: India and the Moluccas. But those were little more than names in a story to people back home—people didn’t understand their geography, let alone their flora. Whenever Christopher Columbus encountered a new plant, he must have sniffed its bark for hints of cinnamon, tasted the flower buds hoping for cloves, and scratched at a root in search of ginger. Then he would have turned his attention to its seeds, home to the most valuable spices of the day—nutmeg, mace, and pepper.*
FIGURE 9.1. Christopher Columbus scoured the New World for any sign of Asian spices, filling the logbook from his first voyage with more than 250 botanical descriptions. While nutmeg, mace, and black pepper eluded him, he did bring home the tasty seeds of allspice and chili peppers. COLUMBUS TAKING POSSESSION OF THE NEW COUNTRY, L. PRANG & COMPANY, 1893. LIBRARY OF CONGRESS.
Scholars often compare the historical craving for spices to the modern appetite for petroleum. Both situations combined limited supply with virtually limitless demand, creating commodities that anchored the global economy. But where oil reserves already show signs of dwindling, the harvest of spices remained constant and even increased, extending their reign for centuries. Tracing that story reads like a history of commerce, exploration, and civilization itself. In ancient Egypt, for example, peppercorns from India’s Malabar Coast somehow made their way up the nostrils of dead pharaohs—they were the royal embalmers’ most prized preservative. When Rome found itself surrounded by Visigoths in AD 408, the barbarians demanded 3,000 pounds of pepper as part of their ransom to end the siege. King Charlemagne issued a decree in 795 that called for cumin, caraway, coriander, mustard, and a host of other flavorful seeds to be grown in gardens throughout the Frankish Empire. Paying feudal tithes with spices became common during the Middle Ages, and the practice still persists: when the current Duke of Cornwall (alternatively known as the Prince of Wales), England’s Prince Charles, officially accepted his title in 1973, he was presented with a pound each of pepper and cumin.
Some of the most telling spice statistics of all, however, boil down to simple economics. In fact, they sound like the prospectus for a stock offering. During its first fifty years, the Dutch East India Company dominated world trade in nutmeg, mace, pepper, and cloves, experiencing one of the greatest eras of profit in the history of business. Gross margins never dipped below 300 percent, and the company paid lavish dividends, both in cash and in spices. Original shareholders who held on to their stock enjoyed average annual returns above 27 percent for forty-six years, a rate that would have turned a modest $5,000 investment into a fortune of more than $2.5 billion over that time. (For comparison, Exxon Mobil—currently the world’s most profitable enterprise—earns total returns of around 8 percent a year.) With that kind of money at stake, it’s no wonder the Dutch happily gave Manhattan to the British in 1674 in exchange for a tiny, nutmeg-producing island in Malaysia. And it’s not surprising, either, to learn that one of the only pirate chests ever recovered—buried by Captain William Kidd in 1699—contained not gold or silver, but a few bolts of fancy cloth and a bale of nutmeg and cloves.
In terms of exploration, however, nothing puts Christopher Columbus’s spice worries in better context than the results of a voyage only slightly less famous than his own. When Ferdinand Magellan set sail a quarter century after Columbus, he promised his backers the same result: a direct western trade route to the Spice Islands. Three years later, four of his five ships were lost and Magellan was dead, along with his second-in-command, third-in-command, fourth-in-command, fifth-in-command, and over two hundred crewmembers. Yet when eighteen survivors limped into Seville on the sole remaining vessel in 1522, they had more to show for their trouble than a global circumnavigation. Their small cargo included nutmeg, mace, cloves, and cinnamon from the Malaccan island of Ternate. When sold, the spices brought in more than enough cash to pay for the lost ships and compensate the families of the deceased, turning the journey into one of discovery and profit. Without finding spices, Christopher Columbus would never manage that feat.
History remembers Columbus for his epoch-making first trip across the Atlantic and for helping usher in a new era of exploration and conquest. But people often gloss over the fact that he returned to the New World three more times, searching in vain for spices, gold, or other valuable commodities. On the second voyage, he found every member of his new colony on Hispaniola murdered by natives. He returned from the third journey in chains, accused of tyranny, and he ended the fourth expedition shipwrecked on Jamaica for more than a year. As one biographer put it, “money was continually being spent on ships and supplies; where was the return for it? . . . What about the Land of Spices? . . . To the most impartial eyes it began to appear as though Columbus were either an impostor or a fool.” While others suspected he’d found something new, the admiral stuck to his claim that the Caribbean Islands and surrounding coastlines were indeed parts of Asia, and that spices—not to mention Japan, China, and India—would turn up in time. But though Columbus would go to his grave without knowing what continent he’d discovered, one thing is certain: he knew he’d found the wrong pepper.
“There is also much aji, which is their pepper and is worth more than our pepper,” he wrote, after dining with the locals on Hispaniola. Though he’d never seen black pepper growing, the difference in flavor and pungency, not to mention the shape and color of the seeds and fruits, told him that this spice was different. His claim about its value can be chalked up as good old-fashioned spin-doctoring. In the waning days of that first voyage, he needed to put the best face on whatever seeds, plants, and scraps of gold he’d cobbled together for a cargo. But in retrospect, Columbus’s words seem prophetic, because by most measures the chili peppers he brought back across the Atlantic have gone on to become the most popular spice in the world.
Dried and ground or added whole, the fruits and seeds of Capsicum chili peppers now flavor everything from Thai curries to Hungarian goulash to African groundnut stew. From four wild species native to the New World, over 2,000 cultivars have been developed, ranging in spiciness from the mildest paprika to the fieriest habañero and beyond. (Bell peppers also come from this stock, but are bred for size and sweetness instead of pungency.) One in four people around the world eat chili peppers daily, and in a twist that might have pleased the frustrated admiral, they’ve replaced black pepper as the hot spice of choice throughout India and Southeast Asia. He may have failed to reach the Spice Islands, but in the end, he did manage to change their spices.
In fact, Columbus and his chili peppers ultimately changed the whole spice industry. By transporting the seeds across an ocean, he showed that chili plants were like any other crop. Given the right conditions, they could flourish far outside their native range. Once this idea took hold, the trend was unstoppable. By the end of the eighteenth century, nutmeg had moved to Grenada, cloves and cinnamon had shown up in Zanzibar, and people had started planting black pepper wherever a tropical vine could climb a tree stump. Cheap product flooded the market, prices plummeted, and spices lost their exotic cachet. Though it remained a valuable enterprise, the spice trade never again sparked wars, founded empires, or inspired voyages of discovery. But for centuries, the lust for spices shaped history, and seeds lay at the heart of it. Seeds still dominate the contents of a typical grocery-store spice aisle, but though people pinch, grind, dash, and otherwise consume them every day, few consider the biology behind that simple act. Why are spices spicy? As it happens, no story answers that question more completely than the story of chilies, the peppers of Columbus.
“It all comes down to seed production,” Noelle Machnicki told me, and she ought to know. As the author of a doctoral dissertation titled “How the Chili Got Its Spice,” Noelle has spent more time thinking about hot peppers than just about anyone. When I caught up with her, she’d recently defended her thesis and was busy holding down two different jobs at different universities in different cities. “I’m sort of living a double life right now,” she admitted wearily, sipping from a large coffee. Noelle has dark hair, dark eyebrows, and an expressive face that can shift from wariness to warmth in an instant. When the conversation turned to chilies, all signs of fatigue disappeared and she suddenly spoke with the enthusiasm of someone who can’t wait to tell you a secret. Her work caps fifteen years of research by the “Chili Team” at the University of Washington’s Tewksbury Lab. Taken together, their research papers epitomize how science is supposed to function: questions leading to insights, leading to new questions, until a fascinating drama lies revealed. For Noelle, it all started with a love of mushrooms.
FIGURE 9.2. Chili pepper (Capsicum sp.). The thousands of varieties of domestic chili peppers descend from four species native to South America. In the wild, their pungency repels seed-killing fungi as well as rodents and other mammals that can’t take the heat. ILLUSTRATION © 2014 BY SUZANNE OLIVE.
“I’m basically a mycologist,” she said, and explained how the prolific toadstools of the rainy Pacific Northwest had helped draw her from her home near Chicago. She studied them on the forested campus of Washington’s Evergreen State College, and then entered graduate school to pursue a particular passion. “I’m fascinated by how fungi interact with plants,” she told me—how they exchange nutrients with roots in the soil and show up everywhere from bark to flowers to the insides of leaves. So when biology professor Joshua Tewksbury asked her to help identify a fungus growing on wild chili-pepper seeds, she was all ears. At the time, Tewksbury had already followed his research on chilies from the American Southwest to the Chaco region of Bolivia, where he’d discovered a species that varied in pungency from completely mild in dry habitats to what Noelle described as “definitely hotter than Tabasco” in wet ones. Intermediate places had the two forms growing side by side, and the only way to tell the difference was to taste them—sometimes hundreds in a day. Luckily for Tewksbury, he’d found the ideal collaborator: a mycologist who liked spicy foods. “I do tolerate chilies better than the average person,” she allowed. But when I pressed the question, she laughed, and confessed to keeping a bottle of hot sauce in her desk drawer at work. “Josh does too!” she added.
The Bolivian chilies presented a rare opportunity. They seemed to preserve that key moment in time when pungency was just evolving. “We know the first chilies weren’t hot,” Noelle said firmly, and explained that all modern species, no matter how spicy, descended from a mild common ancestor. Whatever ecological dilemma caused that distinctive hotness to evolve appeared to be ongoing in Bolivia, where some chilies had made the switch and some hadn’t. If Noelle and the rest of the team could figure out what was going on, they would indeed know how, and why, the chili got its spice. Chemically, the answer was already in the bag.
Scientists long ago traced the pungency in chilies to the presence of capsaicin, a compound produced in the white, spongy tissue that surrounds the seeds. It’s what experts call an alkaloid, a type of chemical that may be more familiar than you think. Alkaloids all share a similar nitrogen-based structure, a set of building blocks that plants have arranged and rearranged into more than 20,000 distinct combinations. The nitrogen matters because it’s a vital nutrient that plants also need for growth, so they don’t use it on alkaloids without a purpose. Usually, that purpose amounts to some form of chemical defense. And because plants usually need to defend themselves against animals, alkaloids almost always have an effect on people, too. They can be spicy, like capsaicin, but that’s just the beginning. Even a short list of common alkaloids includes some of the world’s most recognizable stimulants, narcotics, and medicinals, from caffeine and nicotine to morphine, quinine, and cocaine. In Bolivia, however, few mammals seemed interested in chili peppers, even the mild ones. To Noelle, that made the fungus growing on the seeds look all the more suspicious.
“A fungal seed pathogen is the strongest kind of selection pressure,” she explained. “Seeds are progeny—a direct link to fitness.” In other words, if fungi were killing the seeds of mild chilies, it would give the plants a powerful reason to develop some kind of chemical response. After all, there’s hardly a stronger evolutionary imperative than the life or death of offspring. In an elegant series of experiments, Noelle showed that fungi did indeed kill a large portion of the seeds they infested, and that pungent seeds were significantly more resistant than mild ones. Capsaicin slowed or stalled the growth of a wide range of fungi, both in the wild and in Petri dishes back at the lab, strongly suggesting that it evolved for just that purpose. But her success only raised another question. Why weren’t all the chilies hot? If capsaicin was such a great idea, then why did some plants keep producing chilies as mild as an apple?
Solving that puzzle takes us back to the great square dance of coevolution, the same process of give-and-take that led to strong rat teeth and thick nutshells. In this case, the struggle was invisible, but no less imperative. Noelle’s research showed that both chilies and fungi respond to one another—plants produce more capsaicin as the fungi become resistant, and vice versa. “I think of it as a coevolutionary arms race,” she summarized, but running that race had steep costs for both sides. For a fungus to withstand capsaicin, it gave up the ability to grow quickly—a distinct disadvantage anywhere except inside a pungent chili pepper. For the plants, making capsaicin interfered with their ability to retain water, leading to lower seed production in dry weather. What’s more, it took energy away from the woody material in seed coats, making the seeds more vulnerable to predation by ants. These are serious drawbacks that only made sense under certain conditions, a reminder that the results of coevolution involve more than which partners are dancing. It also depends on where the dance takes place.
Bolivia’s Gran Chaco region stretches from arid savannahs and cactus patches to wet forested hillsides near the borders of Paraguay and Brazil. By sampling chilies across 185 miles (300 kilometers) of mixed terrain, Noelle and her team quickly found a pattern. “In areas of high rainfall, all the chilies are hot,” she told me. “But as rainfall decreases, so does pungency.” For chilies growing in wet forests, where fungi and the insects that move them from fruit to fruit are common, investing in spiciness was a clear advantage. But in arid environments, fungi don’t grow nearly as well, and the potential for water stress and low seed production made pungency a burden. This dynamic of pros and cons put the evolution of pungency in context—a balance between rainfall, insects, fungi, and the physical costs of producing capsaicin. It also helps explain how a change in climate, range, or habitat might have led the ancestors of domesticated chilies to lose their mild forms entirely. When life gets wet and moldy, chilies retaliate with heat.
Most spices will never receive the level of scrutiny that Noelle and her colleagues have given to chilies, but the capsaicin story illustrates a general pattern about the pathway to spiciness. Similar research may one day unravel the mystery behind the myristicin in nutmeg and mace, or the piperine that puts the punch in black pepper. What we perceive as spiciness develops in an intricate coevolutionary dance between plants and their adversaries. Without those relationships, world cuisine would be almost universally bland. This raises a question worth thinking about: Why is it that we add seeds, bark, roots, and other plant parts to flavor meat dishes, and not the other way around?
From pepperoni and pepper steak to pork vindaloo, the zest in our favorite meat recipes always comes from the spices, not from the meat. There is a fundamental biological reason for this. Meat isn’t spicy because meat can move. When a chicken, a cow, a pig, or virtually any other animal is attacked, its capacity for motion gives it a wide range of options: run away, take flight, climb a tree, slither into a hole, or stand and fight. Plants, on the other hand, are stationary. Their lot in life is to stay put and endure, a situation tailor-made for the evolution of chemicals. If you can’t flee or fight back physically (beyond the occasional spine or thorn), it makes perfect sense to repel attackers with alkaloids, tannins, terpenes, phenols, or any of the many other compounds invented by plants. It’s true that insects also boast a wide array of chemical defenses, but they often get them from the plants they eat. Some frogs and newts manufacture poisons, too, and there is at least one species of toxic bird. But the only notable exception to the bland-animal rule comes from the ocean floor, where bryzoans, sponges, anemones, and a range of other creatures spend most of their lives glued to rocks, as stationary as plants. Thousands of marine alkaloids have been isolated from these animals, though it remains to be seen if any of them will prove tasty sprinkled on fajitas, souvlaki, or chicken tikka.
Before the end of our conversation, I asked Noelle what remained to be learned about capsaicin and chili peppers—what were she and her colleagues working on now? The discussion immediately veered into whole new topics, each one as potentially groundbreaking as Noelle’s dissertation. The birds that disperse chilies, for example, appear to be utterly immune to their pungency. They gobble the fruits at will, and the seeds pass through unharmed, or even enhanced, since it appears that moving through a bird helps clean them of fungi. Capsaicin also slows the digestion of birds, forcing them to carry the seeds farther. Noelle told me that the insects moving fungi from fruit to fruit may be chili pepper specialists, and she talked about a student studying how ants differentiate pungent seeds from mild ones. Then she mentioned that someone had recently discovered a fungus capable of making its own capsaicin—though why on earth it would want to is still anyone’s guess. But perhaps the most fascinating line of study has to do with the effect of capsaicin on mammals, which is, after all, the reason that Christopher Columbus packed his hold with chilies, and why they quickly found welcome in spice drawers around the world.
When capsaicin touches the human tongue, sinuses, or other sensitive areas, it produces what chemists describe as “a sensation of intolerable burning and inflammation.” Chefs and fans of hot sauce might describe it differently, but the cause is the same: a chemical sleight of hand that confuses the body’s natural system for detecting heat. Normally, burn sensors in the skin activate only above 109°F (43°C), a temperature that can begin causing physical damage to cells. When you scald your mouth on hot soup, for example, the pain you feel is an honest use of this system. Biting into a pungent chili, however, triggers that response at any temperature. Capsaicin molecules target those same burn receptors and open the floodgates, tricking the body into the kind of pain and rush of endorphins that would normally accompany a serious wound. From the brain’s perspective, the mouth is on fire. The feeling may last for seconds, minutes, or even longer at high doses, but eventually the capsaicin dissipates and the body recognizes that no harm has been done.
For people, this sensation can be enjoyable, the culinary equivalent of a roller-coaster ride or a horror movie—scary, without actually being dangerous. According to some studies, exhilaration from the endorphins peaks only after the burning sensation fades, which raises the paradoxical possibility that we eat chili peppers precisely because it feels so good to stop eating them. Noelle likes spicy food well enough to keep hot sauce on hand at all times, even at the office. But she thinks people developed a taste for pungency only out of necessity, and that chilies entered the human diet for another purpose. “Adding small quantities to food is a pretty good preservative,” she said, noting that capsaicin deters a whole range of microbes in addition to fungi. It’s telling that chilies—and so many other spices—were domesticated in the humid tropics, where meat and fresh vegetables spoil quickly. For thousands of years before refrigeration, having a burning tongue was small price to pay for thwarting mold and harmful bacteria. If Noelle is right, then people started eating capsaicin for the very same reason it evolved: to ward off the fester of fungus and rot.
Without the need to preserve meat stews or pots of beans, no other mammals have developed the chili pepper habit. They feel the same burn that we do, but to them, pain is simply pain. So while pungency may have gotten its start fighting fungi, it’s also extremely good at deterring rats, mice, voles, peccaries, agoutis, and all the other mammals that would otherwise happily devour a chili seed. Where these gnawers are common, that’s an important evolutionary advantage for the chilies, and it almost certainly played a role in determining why pungency became dominant in so many chili species. It also creates a brilliant dispersal strategy: repel the animals that chew and destroy your seeds, leaving more available for the birds, whose pain receptors don’t respond to capsaicin, making them physically incapable of feeling the heat.
When I said goodbye to Noelle, my head was still swimming with chili questions. But that’s the way with science—new information simply feeds the curiosity. The complexity of the chili pepper’s story explains not only how seeds can become spicy, but why spices have so many uses in addition to seasoning. If they evolved to interact with everything from bacteria and mushrooms to squirrels, it’s no wonder that people find spices useful in a lot of situations. In Columbus’s day, they certainly found their way into food, but they also served as popular medicinals, aphrodisiacs, preservatives, and oblations. (Contrary to popular myth, exotic spices were never used to cover up the taste of rotting meat. They cost a fortune and signified status—the people who bought them could easily afford fresh, high-quality ingredients.) In modern times, things haven’t really changed all that much. Capsaicin from chilies—to take just one example—forms the basis of everything from arthritis creams and weight-loss pills to condom lubricants, bottom paint for boats, and the self-defense spray marketed as Mace. Olympic show-jumpers have been disqualified for rubbing it on the legs of their horses, and wildlife rangers in Africa fire it from drones to herd elephants away from poachers. But in China, people use capsaicin for something that most of us associate with a different seed product, one perhaps even more famous than chili peppers.
Chairman Mao Zedong promoted an austere lifestyle with simple peasant foods, but he harbored a famous love of chilies. Even while living in a cave, he ordered them baked into his bread, and reportedly ate whole handfuls to boost his energy while working late at night. Now, police officers in Mao’s native Hunan region regularly distribute hot chilies to sleepy drivers in an effort to reduce traffic accidents. For most night owls, however, the stimulant of choice comes in liquid form, extracted from the seed of an African shrub. Like spices in their heyday, it has spawned vast fortunes, influenced world events, and inspired at least one sea voyage worthy of an adventure story.
*Nutmeg and mace both come from a tree native to Malaysia. Nutmeg is the seed itself, while mace grows as a fleshy red seed appendage called the aril. Pepper comes from a rainforest vine native to the west coast of India. Black pepper includes the seed and a thin layer of shriveled fruit tissue; white pepper is the same thing with the fruit layer removed.
