Ferran Adria: The pot washer who gave cooking a cutting edge

"People think I'm on holiday," Ferran Adrià laughs. "I'm relaxed, but I've only had three days off in the past three months."

It has been that long since Adrià, arguably the world's greatest chef, closed El Bulli, the Spanish restaurant with near-mythical status. Until then, foodies had travelled from around the world to experience the 30-course culinary circus that included spherical olives, foie gras made into dust and peach liquid. But no more.

The chef seems remarkably laid back about the closure. Much more so than the many who once dreamed of getting a table at El Bulli. But then there were always going to be many disappointed gourmands, given that he served only 50 people a night, and more than two million would bid for the 8,000 places available each six-month season. "We are now just closing for a slightly longer period," he jokes, although there is no suggestion that his restaurant will reopen in its previous form. Plainly, he sees his next project as an evolution rather than an ending.

"There's not a big difference," he says. "We're doing what we would do every year, and travelling a lot. The difference now is that we'd usually be working on new ideas for menus; instead we're working on new ideas and concepts."

I meet him and his Spanish translator for lunch – a selection of dishes cooked from his new book, out tomorrow, entitled The Family Meal – at Google's London offices. The book offers step-by-step instructions and photos for 31 meals, each of three courses and costing no more than £3.50 per person, based on the dinners his staff would share together each night at 6pm, before service started.

"In Spain, it's quite common in professional kitchens to talk about the staff as family, because we spend a lot of time together. If you eat well, you work well and in a contented manner," he says.

In contrast to the culinary theatrics that Adrià gave the world – the mojito baguettes, game-meat cappuccinos and fish wrapped in candy floss that his guests ate at El Bulli – the meals shared by staff were straightforward home cooking: pasta and risotto; salads and burgers; Adrià's favourite noodles with mussels. Adrià has lost 20kgs over the past two years, exercising for 40 minutes a day. "The solution isn't dieting," he says. "Most of us delude ourselves, because we don't have the willpower to do an exercise regime."

But he is not turning his back on the avant-garde creations (he dislikes the term "molecular gastronomy", and its associations with science laboratories) that made him world famous. "This is a special circumstance. I am not going to do another cookbook like this for home cooks," he says.

He is also compiling 4,000 pages of recipes from El Bulli, covering the year 2006 when the restaurant was first named the best in the world, until its closure in 2011 (previous recipes, going back to 1983 when Adrià, now 49, joined El Bulli, have already been published).

While documenting a glittering past – Adrià became a pot washer at 18, joined El Bulli as line chef at 22 and was made head chef at 24 – may be enough for most people, he is firmly focused on the future. Perhaps it's a logical progression that his next venture will be dedicated to pushing the limits of cuisine. In 2014, he will open El Bulli Foundation, a place chefs can think about creation and development, away from the kitchen.

Early sketches suggest it will look like a technologically advanced James Bond lair on the original restaurant site, carved out of rock from the Costa Brava coast, with brainstorming rooms, temperature-controlled thermal spaces, sea-facing glass rooms and even a balcony made from bird feathers. Joseph Stiglitz, the Nobel Prize-winning economist and adviser to Barack Obama, is on the advisory board. "The current challenge is deciding the selection process for chefs," says Adrià. "It's about them being really creative."

The foundation will run for eight months a year, with 11 core members of the El Bulli team, and another group of chefs who will vary their lengths of stay. He thinks chefs, such as his good friend Heston Blumenthal, will also want to visit. "People ask, 'Is it really going to take two years to prepare this?' The answer is 'Yes'." And occasionally, people will get to sample the creations. "From time to time, we will serve diners. But guests won't pay; they'll be invited. They won't be able to make reservations."

The foundation is his focus, but El Bulli's legacy is unlikely to fade soon. A museum will open in Roses, near Barcelona, next year, and an exhibition opening at the end of January 2012 will tour cities worldwide, including London. Three documentaries are being made, as well as a Hollywood feature film with a script in progress. "I'm excited. No one has ever made a great feature film about high-end cuisine: there's been Ratatouille, but that was an animation," he says, laughing when I ask who he'd like to play him. "I think it shouldn't be someone too famous. The reason The Social Network's a good movie is because the actors aren't too famous. If Brad Pitt were Mark Zuckerberg, you wouldn't quite believe it."

Adrià's right: it seems wrong to obscure the film by picking too well-known an actor. Especially since his life, which includes working for Pepsi, is strikingly unstarry compared with those of most A-list actors. He's been happily married to his wife, Isabel, for more than two decades; they have no children. "So," he says, "we have freedom to do whatever we want, but we do very normal things: go to the cinema and theatre, eat out. We have normal friends, we dress normally and aren't materialistic, but we enjoy good travels." He is proud of his work for the Alicia Foundation, which aims to generate knowledge in the culinary field and provide strategies to improve eating habits. It recently encouraged record numbers of blood donations, by giving away a little food afterwards.

And while no chef can completely avoid kitchen dramas – Adrià was once accused of poisoning restaurant guests – he remains pragmatic. "Life is made up of people who appear in the photos, and people who don't. And the people who aren't in the photo always want to be," he says.

He has stepped away from his restaurant while it was still at its best. "The transformation has to happen when at the top, not at the bottom," he says. "Otherwise, people start saying you're doing something else because you've failed."

Despite having only three days off since closing El Bulli, Adrià says he is under much less pressure. "I'm doing what everyone would like the chance to do: spending two and a half years learning, travelling, getting new ideas and inspiration, cleaning out my brain so I can think in a different way. If I stopped completely, it would be dangerous." But he doesn't rule out taking a few more days off. "Hang out on a beach in the Maldives? I may do something like at the end of 2012 when I'm totally relaxed."