“I’ve been doing a lot of research, and it really seems to be the case that the legend is the truth,” Lisa said. “Twenty years ago, the Adrià brothers took over a struggling French restaurant up in Roses, and in the nineties they began to collaborate with a chemist here at the university. And, being isolated and inexperienced, they began to do new things. It really did come from two intense brothers who didn’t care what the rules were supposed to be.”

We pulled up in the darkness to a modern glass storefront amid the medieval buildings and parked on the sidewalk. Inside, Jordi Butrón, the chief scientist-cook of the research center, greeted us solemnly and led us into his classroom. On the blackboard behind his head was a series of abstruse-looking diagrams. With a close-shaved beard and mustache, he had more the look of a severe French sociologist than of a happy Spanish cook. I explained that I was on a quest to find out what desserts really were and where they were going. He held up a hand and began to speak, in rapid, accented French.

“In retrospect, they’re disgusting, many of the things we used to do—too much fat and too much sugar, and a series of clichés taught while being rationalized,” he said. “The key thing now for a cook is to develop a library of flavors that you can recall. If I say to you, ‘Apple and cinnamon,’ you would click in immediately. ‘Yes, apple! Yes, cinnamon!’ The library of your mind contains that. But what if I say ‘Apple, asafetida’? Nothing! You have nothing stored there.” He added slyly, “Now, this is a benefit to the chef, because if I do apple and cinnamon and you don’t like it you think there’s something wrong with me, but if I do apple and asafetida and you don’t like it there’s something wrong with you.” He laughed briefly, professionally. “The development of a pastry chef is not the development of techniques. It is the slow, careful development of a catalogue of savors and flavors, which you can develop the way you develop muscles. There is a logic in every dessert worth eating. Consider the logic of white peach and rich cheese. We must be conditioned not by sight but only by flavor, the tongue, the nose, and the feel in the mouth.” He went on placidly, “It is to avoid these errors that we do so much of our teaching and learning blindfolded.”

“Blindfolded!” I said, wondering if I had misunderstood.

“Yes, blindfolded,” he repeated. He went to a drawer and took out a handful of silken eye masks, which he threw on the desk. “It is important to be able to work with the sensations of the nose and mouth alone, so we spend hours in the dark, tasting. Of course, appearance matters, but it is the last part of the equation. Taste, taste, taste—that is what matters. So I keep people blindfolded for much of the work, which is devoted to the marriages of taste.”

Then he opened the door to an immense, pristine kitchen, dominated by a great length of polished black stone. Here, he said, “as many as fourteen young chefs can work, blindfolded, to discover the taste and enlarge their flavor libraries.”

I noticed various pieces of space-age-looking machinery littering the beautiful, dark kitchen, and I asked how the new technology contributed to his work.

“It is useful as tools,” he said crisply. “If I want to capture the flavor of a raspberry meringue, I use a powdered egg white, and then I have a true raspberry in the form of a meringue, instead of a super-sweet meringue overwhelming raspberries.” He shrugged. “Nothing we do with new equipment does more than allow us to reinsert flavors.”

We sat down for dinner in the nearby restaurant, and had a meal of five courses, all sweet, or at least sweetish, yet all beginning with a savory theme. First, there was cucumber-ginger-pineapple-tarragon sherbet, then olive-oil cake with San Simón cheese and a perfect white-peach sorbet. “The combination is a classic conception of the savory kitchen: cheese and olive oil,” Jordi observed. Then came an Idiazábal-stout-beet-cherry cake, too various to make much sense. Then a green-apple granita with bay leaf, as fresh and acid as a winter morning, and, finally, truffle-hazelnut-toast cream pudding. The genius showed in the details: a curry-and-salt cookie, thrown in as an extra but a study in itself. There was something perfectly modulated in the transition from savory herbs (tarragon and bay) and savory tastes (salt and curry, particularly) into sweet dishes.

“This is kind of amazing,” I said to Lisa, as I scraped the plate of truffle-toast pudding and grabbed another curry-and-salt biscuit. Lisa gave me a seraphic, you-ain’t-seen-nothing-yet smile, and said, “You’ll meet Albert tomorrow.”

I sat in my little hotel room in Barcelona, jet-lagged and sugar-satiated, and read about the history of sugar. Primates, I learned, love sweets for reasons that are simple enough to explain: sweetness is the natural sign of ripeness, and the best assurance, especially when balanced with just enough acids, that the thing you’re eating is good to eat. Yet the picture is more complex. The primate instinct for sugar is particular, adjustable, and sometimes seasonal. The lesser mouse lemur of Madagascar, a gourmand among monkeys, raises its threshold during the rainy season so that, when sugars are less abundant, it requires less sweetness. Yet this may be why the lesser mouse lemur has always remained so deeply lesser. Our nearest relations among the primates, particularly chimps, have a “supra threshold”: they love sweets and will practically die to get them—and this, the theory goes, is one of the things that make them forage over extremely large territories, outside the forest. They strolled on all fours, then walked, then ran, just to have dessert.

As both the anthropologist Sidney Mintz and the historian Jean-Louis Flandrin have documented, it was only recently that the instinct for devouring sweets met the availability of abundant sugar. In pre-Crusades medieval European diets, only honey and fruit and other “natural” sweeteners were available, and they were mostly used in savory dishes. For centuries, sugar was a spice as rare as myrrh and as precious as saffron: an expensive extra used to give food taste and color. Only in the Renaissance did sugar slowly, through the New World, become widely current. (“Sweet” became one of Shakespeare’s favorite adjectives: it appears seventy-two times in the sonnets alone, and the first writer who mentions them refers to his “sugar’d sonnets.”)

Then, in the late seventeenth century, the price of sugar plummeted, never to recover, largely as a consequence of that hideous invention the West Indies sugar plantation. The cheap-sugar revolution took different paths in different places. In England, sugar combined with tea became the staple drink of the masses. In France, a full-blown dessert cuisine emerged, with the pastry chef as its hero. Soufflés rose; egg whites lifted up; aerated egg yolks combined; cheaper chocolate was blended with butter to make buttercream; and egg yolks were kept from cooking while allowed to thicken.

Reading the primatologists and the anthropologists, I got the sense that the double life of sweets ever since the sugar revolution—as a thing we universally crave, and as a highly specific, French-derived cooking culture—has led to a strange fight between disciplines. The primatologists insist that we eat sugar because our genes scream for it, while their humanist colleagues insist that sugar is above all a cultural symbol—we eat as many sweets as we can in order to emulate the rich, who usually get to eat more. Yet surely an artifact and an appetite are not opposites to be reconciled but the same thing seen at different moments in its history. The lesser mouse lemur would doubtless devour a crème caramel and a butterscotch pudding indifferently; it takes a pastry chef trained in France to state the difference. The artifact gives the appetite shape; the appetite makes the artifact shine.

The next morning, I met Albert Adrià at the workshop that the Adrià brothers keep in the old quarter of Barcelona. In jeans and a work shirt, Albert had the stocky, proletarian look of a young Braque or Léger. He is a classic younger brother—earnest, hardworking, self-critical—and he explained the rise of the Barcelona dessert as a series of accidents disciplined by labor.

“Postres?” he asked. “Why me for postres? First, because the pastry chef left. I had just finished moving through all the other stations, and I was due to be at the dessert. And I also have a severe allergy to shellfish, which limits my movement. But the real reason was that pastry seemed much more interesting—a world without limits. Meat cook? Fish cook? What are you going to do with it? And also there was a lot more to learn in pastry—just the techniques! My question was, Why can’t you serve main dishes that are sweet, and why can’t you have savory tastes during the dessert time period?”

I asked when the new style had first appeared. He furrowed his brow, trying to recollect something that had clearly not been the result of a deliberate plan. “It was an accident of the kitchen, really. I suppose we first made an ice cream with saffron in 1985. My first step is, I have to draw it. I have to sketch it, get it down on paper, and then do the explanatory texts.” He began to draw on paper. “This one I wanted to take up, this dirt—one of my most famous desserts involved dirt. A sweetened illusion. The idea came when it was winter at elBulli and I was going up the hill to get my car, and stuff was falling down, and I thought, Shit, that’s good! I can use that! It’s a dirt road, and, in the course of the fall, I noticed not only how the leaves changed color but also how they changed the color of the ground.” The dessert, as it was eventually plated, included cherry sorbet, salted honey yogurt, frozen chocolate powder, and spice bread, all evoking one fall moment: a dessert of frozen time.

Struggling to find words for his inventions, he began to speak about his most recent work: two desserts for the upcoming “Cook It Raw” conference, in Lapland, which would emphasize low-energy techniques, uncooked food. “Elemental, elemental,” he said. “That’s what I want. The really new idea I have for Lapland is—you see, I was thinking, if you were thirsty there you would eat the snow or the ice, and if you’re hungry you’re going to kill the reindeer. So: blood! The most basic thing is to drink the reindeer’s blood and eat the snow. So we made sweet snow and sweet blood. The key for the blood is your belief that it is. It looks like real blood only at forty degrees—it’s a beet-and-orange reduction, and the texture, I promise, is exactly the same as blood. So we’re not telling people that it’s not real blood. It’s meant to be provocative. But it’s very delicious.”

“Is there anything that didn’t work out?” I asked. “Something that you tried and failed at?”

“A lot,” he said. “One of the first things that Ferran asked me to do is create hot ice cream.”

Hot ice cream! He nodded gloomily. “You would look at it—ice cream—and then you would taste it, and it would be hot. Every year I thought I had it! But I never had it. What we discovered was to use an ice-cream machine but invert it, so that it was pumping in hot air, and to use gelatin to get the form. That was as close as we could get. It’s still this idea that we have.” He shook his head. “A sort of dream. I have a lot of them.”

By now, the story of elBulli has become part of modern cooking lore: how the combination of science and culinary curiosity created a real revolution in cooking, with high-tech equipment borrowed from the mass-produced-food industry for the purpose of wild, semi-surrealist picture-making. And how, at the height of this fame, Ferran announced that he would close the restaurant in 2011 and devote himself to “a foundation for pure research in cooking.” (What admirers of elBulli often forget to tell you is that it is a very hard place to get to. You weave your way there on narrow, winding cliff roads along the Spanish coast. The terror of the ascent surely adds to the delight of the arrival.)

A coconut iceberg floats on a sea of lemon gelatin and water ice, with squash confit, mint-and-vanilla ice cream, broken chocolate cookie, and grape-syrup oil slick. Photograph by Francesc Guillamet / Courtesy elBulli Photograph by Francesc Guillamet / Courtesy elBulli

If Albert is a Braque—a stolid man with a poetic imagination—Ferran is very much a Picasso, a grand maître who knows it. Like every first-rate artist, he has the kind of immense egomania that is oddly impersonal: his greatness is so uncontroversial to him that it is an act of generosity to try to limit it in words and dates. There is a certain kind of artistic egotism that is enveloping rather than narrowing: less “All I care about is my work” than “If you only cared about my work as much as I do, you would be as routinely elated as I am.”

I asked dutiful questions about the history, and the future, of desserts, and Ferran responded instantly, in Spanish, not with the guarded caution of his younger brother or the academic certainty of Jordi Butrón but with eager, nodding, flowing eloquence. His guttural, consonant-driven Catalan accent made everything he said sound as though he were murmuring a list of Jewish holidays. “Let us go all the way back to Carême and then come forward to us! Hmm. The problem! The problem! The phrase ‘molecular gastronomy’ I don’t like. ‘Techno-emotional’?—I’m not crazy about it, but let’s use it. Now let’s look at the history of desserts.”