Jim Denevan, one of California's top chefs, is a great believer in feasting al fresco. But getting to his special suppers can involve climbing a mountain or wading to a sea cave. Robin Barton dines with his boots on

Surfer, chef and beach-based artist, Jim Denevan is a very Californian interpretation of Renaissance man. Denevan's day job is as executive chef of the Gabriella Café in the beach town of Santa Cruz, the self-proclaimed birthplace of surfing in California. But each spring since 1999 he has fired up a red and silver 1953 FLXible bus and set off across the United States, championing organic, locally produced food and great wines at a series of weekly, open-air dinners across the United States.

It's not only the meals, produced by a series of guest chefs and winemakers, that are special, but their locations - because to enjoy a Denevan dinner you might have to get your feet wet or your hands dirty.

Denevan's summer road trip, called Outstanding in the Field, delights in bringing diners to settings as extreme as Californian mountaintops, sea caves, tidal flats in Washington state and even icy Alaskan valleys, and treating them to meals such as spit-roasted wild boar. It brings a whole new meaning to "wild food". The 2006 tour made 17 stops, and the al fresco adventures included pre-dinner foraging in a redwood forest south of San Francisco - identifying and picking porcini and chanterelle mushrooms and serving them with Dungeness crab, walnut cake and candy-cap mushroom ice cream for dessert - and an open-air dinner in an East Village park in deepest New York City.

Denevan, a 6ft 4in surfer born and raised in Santa Cruz, comes from a family that thrives on adventure. His sister, Tish "The Fish" Denevan, is a world champion bodysurfer, while Denevan got into cooking simply so that he could work by night and surf during the day.

"I want to grade our dinners like white-water," he has said. Denevan's dinners are much more than picnics with attitude. The sort of issues he has to wrestle with include, how do you get trestle tables, white tablecloths and fine glassware, plus food and wine, into a remote sea cave at low tide and guide 80 diners on a mile-long hike through the sand and back before the tide comes back in? The logistics, he admits, can be challenging, for what must have been a Class Four dinner.

But, particularly in California, the dinners have been a hit with foodies who have a taste for the extreme. After all, how many other dinner invitations recommend wearing warm clothing, walking boots and sunscreen?

What is the appeal for a visitor to the US? Simple: it's a much better way to meet people and make friends than simply bumping elbows at the hotel buffet. For example, at an Outstanding in the Field dinner in Santa Cruz's Bonny Doon winery to benefit a local homeless charity, the Homeless Garden Project, I happen to sit opposite the charity's executive director, Dawn Coppin, who turns out to be a schoolmate from Hampshire. You never know whom you'll meet at a Denevan dinner, and the unusual locations mean that it's never difficult to break the conversational ice.

Denevan's merry band includes Katy Oursler, an effervescent New Yorker in charge of "everything", and dreadlocked cook Barry Boullon, part of Denevan's Santa Cruz team. Oursler's responsibilities include keeping the bus on the road, with the help of driver Caleb Coe, and convincing health inspectors that eating dinner on a mountaintop is perfectly safe. As she welcomes guests to the Bonny Doon premises - this is a fundraising event for the charity, which helps homeless people to farm their own plots, so this time the guests haven't had to scale any mountains - Barry prepares the wild salmon, caught by a local fisherman in Santa Cruz's bay, and rolls gnocchi.

The winemaker for the day is Randall Grahm, the ponytailed founder of the Bonny Doon vineyards and a legend among American winemakers. "These dinners are unique," says the man nicknamed The Rhone Ranger. Grahm shares Denevan's fervour for organic produce, and the two complement each other perfectly; Grahm loquacious and intense, Denevan laid-back and reflective.

And meeting the people behind the meal is another reason to reserve a place at an Outstanding in the Field dinner, for which you will have to fork out from $130 to $170 (£67-£87). During his annual road trip, Denevan ropes in a series of guest chefs and winemakers to produce gourmet meals under the wide blue skies of America and, as he puts it, "it's not every day you get to sit next to the person who planted the beans, raised the lamb and shaped the cheese on your plate".

Nor do you get wine-tasting tips from the creator of the evening's wines at the average restaurant. "Californians are more aware of where their food comes from," explains farmer Jeff at the Santa Cruz dinner. But while California, led by chefs such as the San Francisco restaurateur Alice Waters (a guest chef at Outstanding in the Field), is a hotbed of farmers' markets and organic produce, that's not true of the rest of America, especially when it means walking or even climbing to the dinner table.

"You wouldn't believe how hard it is to persuade people in some places to eat outside," says Oursler. "We've had dinners where just six people have turned up."

That was in the early days, though. Today, Denevan's farm dinners are frequently oversubscribed, with people eager to make a break with the industrial scale of American farming. About 5,000 people have so far enjoyed the Outstanding in the Field experience.

It's an idea that Denevan would like to introduce to Britain. He is also an accomplished land artist (think Andy Goldsworthy in surf shorts), having exhibited at the Yuerba Buena arts centre in San Francisco, and it is an ambition of his to create some of his pieces at the Tate St Ives gallery in Cornwall. Not least, one suspects, because there is some good surfing at St Ives's beaches.



For details of Outstanding in the Field's 2007 schedule around the US go to outstandinginthefield.com. For more information about Santa Cruz visit santacruzca.org.