CHICAGO — Nearly 90% of Americans ate a sandwich within the past week, according to research firm Datassential. Most servings were prepared and consumed at home, but with the lunchtime staple served in more than 70% of restaurants, operators are piling on the innovation. Recent launches from top quick-service chains feature premium positioning, artisan-inspired breads and trend-driven toppings.

“We wanted to know what consumers were already eating, what they were interested in trying and how that compared to the sandwiches that operators were menuing,” said Brian Darr, managing director at Datassential.  “The popularity of sandwiches allows restaurants and retailers a broad platform on which to develop new appealing varieties along with tried-and-true favorites.”

Bakery-inspired buns

For 42% of consumers, the bread or bun is the most important part of a sandwich, Datassential said. From brioche to ciabatta, upscale carriers are dressing up more drive-thru dinners.

Buns have moved from a supporting role to the spotlight at Wendy’s, which over the past two years has launched a string of limited-time offers on ciabatta, brioche, pretzel buns and a multi-grain flatbread made with flax seeds, cracked wheat, rolled oats, millet and sesame seeds. The chain’s limited-time pretzel bread offerings proved so popular, they have since been added to the permanent menu. Pretzel bread grew 33% over the past year on sandwich menus and 150% over the past four years, popping up at such chains as Ruby Tuesday, Chili’s and Red Robin.

Flatbreads also are rising on restaurant menus. This year, Panera Bread introduced a line of flatbread sandwiches in Southwestern chicken, Mediterranean chicken and Thai chicken varieties. Representing the bakery-cafe’s first bread addition to its sandwich lineup in several years, the Indian naan-style breads are baked with whole grains and Greek yogurt, then folded, filled and grilled.

Between the bread

Meat is the key component of a sandwich for 38% of consumers, who typically pick turkey or ham for homemade sandwiches and chicken for sandwiches purchased away from home. Servings of breaded chicken sandwiches have grown on average 3% over the past four years in U.S. food service outlets, according to The NPD Group, Chicago, on the expansion of chicken restaurant concepts and a consumer perception of healthfulness. Fast-food offerings are getting fancier, paired with gourmet condiments and cheeses and bakery-inspired breads. Einstein Noah in October added the Bavarian Chicken Sandwich, featuring a chicken breast topped with beer cheese spread, Applewood bacon, lettuce, tomatoes, red onion and honey mustard served on a pretzel roll; and the Napa Valley Chicken Sandwich, which has a chicken breast and melted Brie cheese, sweet fig jam, red onion, organic arugula and a spread of garlic aioli on a potato roll.

Another hot trend is spicy sauces. Earlier this year, Jack in the Box introduced Jack’s Blazin’ Chicken Sandwich, topped with a ghost pepper-ranch sauce and Swiss-style cheese. Sonic Drive-In during the summer launched a pair of sweet and spicy habanero chicken sandwiches.

Beyond the brown bag

Smoked, saucy meats are gaining traction on quick-service sandwiches. Quiznos, Subway and Wendy’s this year have rolled out pulled pork for a limited time, and Arby’s debuted a barbecue brisket sandwich, with slow-smoked meat on a Kings Hawaiian bun.

“Supermarkets need to start leveraging these trends by adding more prepared foods, including prepared sandwiches and other deli options,” Mr. Darr said. “Today’s consumers are encountering a wider variety of sandwich options and flavors, from regional and ethnic influences to healthier ingredients and quality-driven descriptors like ‘slow-cooked’ and ‘hand-carved.’”

Biting into breakfast

Recognizing a demand for heartier, handheld breakfast items, Starbucks this year added four sandwiches to its morning menu, including a slow-roasted ham and Swiss cheese on a croissant bun, vegetable and fontiago cheese on a ciabatta bun, egg and cheddar on multigrain toast, and reduced-fat turkey bacon with egg whites and reduced-fat white cheddar on an organic wheat English muffin. The items delivered 40% growth during the company’s third quarter.

And on the success of its sandwich platform, Dunkin’ Donuts has reconfigured some of its kitchens with a designated sandwich station to improve efficiencies. Executives of Dunkin’ Brands discussed the development during the company’s analyst day in September.

“So the L.T.O. strategy, the new menu innovation created a lot of great products, and we came to realize, and you guys gave us feedback and our guests gave us feedback that we had a bottleneck at the sandwich station and that we needed to improve that,” said Weldon Spangler, vice-president, U.S. and Canada operations at Dunkin’ Brands. "So we had a cross-functional team working with franchisees, who did a lot of work in developing kind of the perfect sandwich station.”