Interns created the Grilled Marinated Eggplant sandwich through a Fresh Air Fund program. Ten percent of the profit from every sandwich sold this year benefits Fresh Air.

For national chains trying to get in step with this trend, the challenge comes in trying to merge the yin of sourcing ingredients locally with the yang of ensuring product consistency. Most have not made much progress. Smaller regional chains, however, such as chef Tom Colicchio’s New York-based ’wichcraft sandwich concept, are taking their local buying practices with them as they go national.

With 10 units in New York, one in Las Vegas and a new restaurant that opened last year in San Francisco, ’wichcraft has strong ties with New York area purveyors and is developing relationships with new vendors on the West Coast.

Forty percent of the ingredients that make up ’wichcraft’s 21 sandwiches are sourced locally. “It takes work and commitment, but we’ve always done it this way in New York. It just makes sense to do it in San Francisco and wherever else we go,” says partner Sisha Ortuzar.

Costwise, Ortuzar estimates purchasing local ingredients saves ’wichcraft about 20 percent. With some products, it can be as high as 50 percent. “But the costs we’re comparing here are for highest quality ingredients that can take more legwork to find,” he qualifies.

Making farmers-market produce into jams and jellies is ’wichcraft’s method for adding summer sparkle to peanut butter sandwiches year round.

For example, ’wichcraft used to import tuna from Italy for the Sicilian Tuna Sandwich, which features tuna marinated in olive oil with oregano, red onion, capers and red wine vinegar and served on a baguette with marinated fennel, preserved lemon slices and chopped niçoise olives. The tuna came packed in oil in 4-pound tins. “I wanted to eliminate all of those cans and the charges associated with the exchange rate and import taxes,” says Ortuzar.

The company found a six-family co-op of Southern California fishermen that specializes in line-caught tuna with extremely low mercury levels, enabling it to switch to a local product this past fall without sacrificing taste or quality. “Now we’re paying for the tuna, rather than the tuna’s travels,” Ortuzar says.

The California tuna costs about the same as the tuna import if you include the exchange rate and import taxes. “But the quality of the new tuna is much higher and eliminates the middlemen,” he explains. That farmer-to-table exchange is another reason buying local is so attractive to ’wichcraft. “If I buy straight from the producer, I always know what I’m getting,“ Ortuzar says. “When you buy through a distribution chain, the longer the chain is, the less likely you know where that food came from.”

He admits that ’wichcraft does pay to have some ingredients shipped. “Otherwise, our winter sandwiches would be limited to potatoes, onions, squash and apples,” he laughs. The bacon, ham and artisanal pastrami supplier in San Francisco ships pastrami to the New York restaurants, “because since Pastrami King moved out of Queens, you just can’t get this kind of pastrami in New York anymore,” Ortuzar says.

Osmosis-cured, and then smoked over hickory wood and fully cooked, ’wichcraft’s pastrami is made in San Francisco by David Kane, host of the “A Matter of Taste” radio show.

Ortuzar says he’s also expanding the amount of farmers’ market ingredients he pickles and preserves. Lemons are preserved following a five-day process. There’s also a tomato relish, pickled pepper relish and cabbage for sauerkraut.

Although ’wichcraft does not add many new menu items, its summer internship program ensures that at least one new sandwich will get menued each year. It works with the Fresh Air Fund, a longtime New York philanthropic group that gives low-income, inner-city youth summertime opportunities, to bring several kids into ’wichcraft’s kitchens. ’Wichcraft trains the interns in basic kitchen skills and takes them on visits to farmers’ markets. Training culminates with the creation of a new sandwich. It must be menued all year, but the sandwich may have some local ingredients.

Launched in October, the Grilled Marinated Eggplant sandwich is the second creation from the program to wind up on the ’wichcraft menu. It contains marinated eggplant, chickpea spread, balsamic-tossed watercress and grilled red peppers on specially designed bread. The ingredients are sourced locally during the summer; a local baker supplies the bread year-round.

“We charged the kids with creating a vegetarian sandwich that had enough heft to appeal to meat eaters, too,” says Ortuzar. Working on various ideas, the team spent an entire week on eggplant, moving on to research ingredient combos that worked with the vegetable. Then came marinades, breads and spreads. Initially, the team planned to spread the bread with garlic mayonnaise, but later decided to eliminate the mayo to make it a vegan sandwich. They chose chickpea spread instead.

Interns at first built the eggplant sandwich on long, skinny pull-apart bread. But it was too soft and didn’t hold up. “So we went to the baker and worked with them to develop a ciabatta-roll-like version that still had the texture and taste they wanted,” says Ortuzar.

Focusing on fresh and local, both with breads and young sandwich makers, fits neatly into ’wichcraft’s philosophy. “With local, there’s a tendency in our industry to focus on the marketing value,” Ortuzar says. “But we think it should be a more thoughtful thing, focused on improving the flavor of your ingredients and what you can do to reinvest in the economy and health of your community.”