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The best meal of my life, or at least the most memorable, came from a can. I was thirteen at the time and living in France, so that may have had something to do with it. But I credit the beans. My older sisters and I were at a hippie camp in the Alps that summer, not far from the Italian border. My parents had stashed us there while they went home to Oklahoma to check on our house, which they’d rented to some graduate students while my father was on sabbatical. The camp was the cheapest one they could find, and they seemed to have done next to no research before signing us up. My mother just loved the name: Jeunesse du Soleil Levant, Youth of the Rising Sun.

As it turned out, we rarely woke before noon. The camp had promised a vigorous program of crafts, hikes, and team-building games, but the counsellors were usually too hungover, or too caught up in their tent-hopping romances, to bother. (On the last day of camp, I found a stack of unopened boxes behind the mess tent; they were filled with modelling clay and watercolor paints.) We spent most afternoons playing cards and plunking guitars, killing time till after dinner, when we’d hike down to the village to drink beer with grenadine and dance to French disco music.

It was paradise, mostly. The exception was the few mornings when our counsellors, seized by a spasm of conscience, would roust us from our tents and lead us on forced marches through the mountains, declaring that this was what summer camp was all about. It was on one of those trips, on the shore of a frigid lake, that I had the meal of my life. I was famished by then and wobbly with fatigue. I’d spent too many days lounging around, and a counsellor had stuffed two giant cans of cassoulet in my backpack before we left. French trail mix. When we pried them open for dinner, there were only white beans inside, flecked with salt pork. They had one flavor, one texture, one purpose—to fill my stomach—but that was enough. Hunger is a simple thing, an alarm bell in the brain. Sometimes there’s nothing better than shutting it off.

I thought about that meal last spring, when I first met Steve Sando. We were standing at a table heaped with hibiscus flowers, at an outdoor market in the town of Ixmiquilpan, three hours north of Mexico City in the state of Hidalgo. It was a Thursday morning in May, and the stalls were full of women gossiping and picking through produce: corn fungus and cactus paddles, purslane and pickling lime, agave buds and papalo leaf that smelled of mint and gasoline. Sando, who is fifty-eight, ambled among them in a white guayabera shirt, untucked at the waist. He had on loose jeans, tennis shoes, and a bright-red baseball cap that said “Rancho Gordo” above the bill. He could hardly have looked more American, yet he fit in perfectly somehow. He was built like a giant bean.

That may seem too easy, beans being Sando’s business. But people are often shaped by their obsessions, and in Sando’s case the similarities are hard to miss. His body is mostly torso, his skin both ruddy and tanned, like a pinto. He makes a colorful first impression, gets a little starchy if you crowd him, then slowly softens up. Fifteen years ago, when Sando founded Rancho Gordo, he had no food-retailing or farming experience. Now he’s the country’s largest retailer of heirloom beans and a minor celebrity in the culinary world. He’s a side dish who’s become a staple.

“This to me . . . it just makes me so happy,” he said. He was holding a bag of rayado chilies, smoked over an oak fire. He stuck his nose deep inside and inhaled. Weeks later, in my pantry at home, a jar of these chilies would abruptly blossom with black moths, hatched from eggs embedded in their flesh. But Sando was just thinking how great they’d be with a mess of beans. We passed tables of epazote, an herb said to prevent flatulence, and bowls of a greenish-gray soil with a vaguely vegetal smell. “Pond scum from Lake Texcoco,” Sando said. “We use it to soften beans.” To Sando, everything in Mexico seems to connect to beans, and through them to the rest of world cuisine. When he’s at home, in Napa, California, he sometimes gives talks at local elementary schools. He starts by asking the kids where pizza comes from.

“Italy!”

“Wrong. Mexico! That’s where tomatoes are from. What about chocolate?”

“Switzerland!”

“Nope. Mexico! That’s where cocoa beans are from. How about vanilla?”

“Mexico?”

“That’s right! And chilies, corn, and squash, too.” Many of the staples of European and Asian cooking came from Mesoamerica via the Spanish, he explains. It’s called the Columbian Exchange, but it wasn’t much of a trade for the Mesoamericans. They got turnips, barley, and spinach.

Sando is a rather sheepish addition to that history. He’s uneasy about import regulations, fretful of cultural appropriation, and well aware of his fumbling grasp of Mexican custom. “I’m not the Indiana Jones of beans,” he told me. “I’m the Don Quixote.” Every year, he takes one or two trips to Mexico to look for rare varieties and farmers who might grow them for him. He was in Ixmiquilpan to search for an especially elusive quarry: Flor de Durazno, the Flower of the Peach. This was a dainty, pinkish-brown bean of uncommon taste and velvety texture, grown in Hidalgo. Sando had seen it once in his life, in a package sent to his office by a farmer not far from this market. He was hoping to buy two thousand pounds for his Bean Club.

I happen to be a member of the Bean Club, though I’m a little reluctant to admit it. Not that it isn’t a pretty exclusive thing. Anyone can buy beans from Rancho Gordo, but the Bean Club—which sends members six rare varieties and a few other oddments, like blue hominy, every three months—closed its rolls last year. Sando couldn’t keep up with demand. Still, admitting that you’re obsessed with beans is a little like saying you collect decorative plates. It marks your taste as untrustworthy. I’ve seen the reaction often enough in my family: the eye roll and stifled cough, the muttered aside as I show yet another guest the wonders of my well-lit and cleverly organized bean closet. As my daughter Evangeline put it one night, a bit melodramatically, when I served beans for the third time in a week, “Lord, why couldn’t it have been bacon or chocolate?”