There is something decidedly fishy about Ferran Adria, head chef at elBulli. Something not quite kosher. He’s not what he seems. In his uniform, he looks like a chef. The waiters treat him like a chef. And the menu says he’s a chef. But he doesn’t sound remotely like a chef. In all my years as a chef-wrangler, I have learnt one immutable rule about these little critters: they don’t ever, ever, ever mention the customers. Chefs will pontificate on recipes, declaim on the virtues of pigs and the beauty of chickens; they will whisper words of love to turbot, talk dirty to radishes. They have opinions on other chefs, and loathing for critics. But they have absolutely, positively nothing to say about the guests. They even use a diminishing, distancing term: you’re “covers”, and are counted like sheep, but not as appreciated as lamb.

Adria gives the game away by actually talking about the people who eat in his restaurant. Not as numbers, but as members of his species. As individuals with characters. He also refuses to discuss his food or recipes. “I don’t like to talk to the customers about what they’ve eaten here, or about the food. What are they going to say to me about it? That the rabbit brains and oyster could do with a little more seasoning? They’ve never eaten my food before. They have nothing to compare it with. My brother, though, has a very good tapas bar in Barcelona. If somebody said to him, the croquetas need a little more salt, then he listens. Maybe adds a little more salt. Everyone has an opinion on croquetas. But my food, no.”

That’s not strictly true. Thousands of people have opinions about the food at elBulli, and most of them have never eaten it. Before I even got here, three widely and well-fed friends told me exactly how ghastly it was going to be, how pretentious, how phoney and inhospitable. Not one of them had actually been. “Why would we?” they snorted. “It’s so awful.” Great success, particularly with food, brings an equally great disdain from people who like all their epicurean pleasures to be rare and exclusive. Being told your favourite restaurant is also the favourite of every guide and gourmand in the world is a bit like being told you’re a lucky guy because your fiancée was the best shag any of us ever had.

Besides, getting a table at elBulli, in Girona, Spain, is an infuriating performance. The restaurant is open six months of the year. There are 8,000 chairs available, and 2m requests for them. Every one of them gets a courteous reply; most of them never get to smell the coffee. The few who do are told what date and when to come. It’s actually easier to get a seat next to the Pope than in elBulli. Adria is unapologetic. He shrugs. What else can he do? The place is popular. This is the fairest system, and fairness is important to him, being straight with people, respecting them.

Our interview is a slow and complex thing. He speaks Catalan; I don’t. I speak English, and, by coincidence, so does Adria. He just pretends he doesn’t. So we have a nice lady translator, and Adria uses the time between translations to compose pithy, intelligent replies, which he says in Catalan, and then, after a bit, I hear in English, but, occasionally, he’ll jump in, to correct the translation.

I’m constantly nagged by the suspicion that he really isn’t a chef: he doesn’t really talk about himself, but, when he does, it’s not in the third person — all chefs talk about themselves in the third person — but with an awkward shyness. He’s clever and modest, and funny, in a Catalan sort of way. And bizarrely lacking in any of the megalomania that is the defining characteristic of men who wear white hats and cook dinner. For instance, the obvious answer to the avalanche of demands for his food would be, simply, open another restaurant. Or 10. “Look,” he says carefully, “I don’t want to be rude about other chefs. Believe me, I think gastronomy would be poorer without Alain Ducasse, or Joël Robuchon, or” — he pauses to remember a name — “Gordon Ramsay. But, for me, and I only speak for me, I can cook only in one restaurant at a time. It is impossible that there could be another elBulli.”

Well, you could open the other six months and do lunches. He laughs. At a time when most successful chefs are doing their damnedest to get out of their kitchens, wear their white uniforms only for publicity shots, and measure their success by television appearances and gossip-column inches, Adria dodges most publicity and still works at a stove. He cooks for six months, and only dinner, because that’s the way it keeps on being exciting, a calling, rather than an obligation and a misery. The rest of the year he tinkers with new dishes and travels. He’s very taken with the tastes and presentation and obsession with ingredients of the Japanese. He likes their odd, manufactured, plasticky flavour, and uses the extremely citric fruit of the rainforest, although he insists his food is rooted firmly in this place, on this coast, informed by the weather, the light, the history and that most vital of chef’s ingredients, the tastes of his childhood.

Thus elBulli is a flagship for an armada of new Spanish cooking. But it quite plainly isn’t Spanish. It belongs not to any stretch of land or nostalgia, but to the galloping imagination of one man. Very, very few chefs manage to so completely disengage their craft from the dishes and flavours of their contemporaries and compatriots as he has. The staff here outnumber the customers. The kitchen is beautifully designed, far nicer than the restaurant. It has moody lighting and decorative sculptures, and, most innovatively, a workspace that is egalitarian. Chefs here work facing each other, in a collegiate synergy based on mutual help, rather than in the old French hierarchy based on orders and fear. Remarkably, most of these cooks are trainees, gathered from all over the world. They are the best of the best and they stay here for seven to eight months. Every year, two-thirds of his staff will be replaced. Compare that with most three-star kitchens, who resort to bribery and threats to keep their minions for ever. Adria actively sends his out into the world, not as competitors, but as missionaries. His food is not made from years of practice, repetition and experience, but from huge infusions of effervescent, fresh enthusiasm. This is not only the most sought-after restaurant in the world, it is also the most sought-after job in catering.

Adria takes his role as a teacher seriously. He has produced a book. He says it’s for people who can’t come here to the restaurant, so they can have a virtual hint of what it is he does. He’s gone about the book in a characteristically focused, detailed and exhaustive way. It weighs as much as a toddler and describes a single day in 528 pages, which is possibly slightly longer than the other most famous single day in literature, Ulysses. And, indeed, he’s not unlike a marzipan Joyce. The paper wrapper of the book identifies Adria as the best chef in the world, and elBulli as the best restaurant in the world — eye-rolling honorifics that he says are meaningless, a hindrance. What it doesn’t say is that Adria is unquestionably the most influential chef since Escoffier. But his influence has not always been an improvement. There are thousands of cuddish, foamed sauces dribbled over insipid little dinners that claim to owe their inspiration to a coarse imitation of elBulli.

But two of the lessons from elBulli have have not been learnt so fast. One is perfectly simple: eating with your fingers. Wherever possible, he insists we should use our hands. The experience is intimate, natural and more thoughtful. And the other is more difficult for chefs to accommodate than a whisked-up jus. Adria’s cooking is first and foremost about being good to people, caring about them, being interested in them, both those who come to eat and those who come to create.

A Day at elBulli is published by Phaidon at £29.95, and is available from The Sunday Times Booksfirst for £26.95 (inc p&p) on 0870 165 8585 or at timesonline. co.uk/booksfirst. elBulli, Cala Montjoi, Ap 30, Roses, Girona, Spain; 00 34 972 150457.

AA Gill travelled courtesy of the Spanish Tourist Office; 0845 940 0180, spain.info/uk

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