America's fast-food and fast-casual burger chains number more than 45,000, so new entrants to the burger wars better stand out. Some are relying on a surprising recipe for success. It's not a secret ingredient so much as it is a key ingredient they are leaving out. "I would say the big differentiator with us is over half of our sales are actually non-beef," said Ashley Sawyer, director of Burger 21 franchise development.

Burger 21’s Ahi Tuna burger includes sushi-grade tuna, sriracha aioli, caramel soy and avocado. Source: Burger 21

The chain, with 24 locations concentrated in Florida and Georgia, offers 21 different patties, with only 10 beef options permanently on the menu. Non-beef options include seafood, veggie, chicken and turkey patties. The tuna burger, for example, contains sushi-grade ahi tuna, sriracha aioli and caramel soy and avocado, combined with more traditional burger toppings, like lettuce and tomato. The Greek is a veggie burger with roasted peppers, a feta spread and pickled cucumbers. The 21st burger on the menu rotates on the 21st of each month, allowing the company to test out new ideas. "We're not just checking another box off the list," Sawyer said. BurgerFi is a good place to examine the existential crisis of the classic beef patty. The Florida-based chain, with 88 locations (it owns 20 percent of them), is trying to cover every potential burger customer, and that includes a very small customer niche that it is more or less in the process of inventing.

Its classic BurgerFi cheeseburger is the chain's most popular. It also offers a veggie burger, called the VegeFi burger, made with quinoa, lentils, carrots, zucchini, sauteed mushrooms and onions. It accounts for close to 15 percent of sales.

But for a small group of customers who can't decide between the beef or veggie patties, BurgerFi features the Conflicted Burger, which contains both a natural Angus burger and veggie burger. It generates about 3 percent of burger sales.

BurgerFi's Conflicted Burger includes both a beef and veggie patty. It generates about 3 percent of burger sales for the company. Source: BurgerFi

"It's not a gigantic seller. It's a little popular, but it's one of those ones where people talk about it quite a bit. They get a big laugh out of the name," said Steve Lieber, BurgerFi's global brand ambassador.

Burgerim, a new fast-food franchise import from Israel, boasts turkey, lamb, chicken, salmon and veggie patties in addition to its beef burgers. This summer its first U.S. location opened in Los Angeles, and close to 30 will be open by the end of the year. But Burgerim is also making a play for the traditional burger eater, boasting about the quality of its beef patties and recommending customers leave out other key ingredients — namely, cheese and ketchup.

"It's kind of like the idea if a steak is good, you shouldn't need to put ketchup on it. It's kind of the same idea. The natural flavors are so good, you don't need to put cheese or all these sauces on it, even though we have a variety available," said Jesse Crow, the chain's national corporate success manager.

I would say the big differentiator with us is over half of our sales are actually non-beef. Ashley Sawyer director of Burger 21 franchise development

The number of new entrants in the burger niche is concerning, since it's the largest fast-food category and overall growth has slowed. McDonald's same-store sales in the United States didn't quite stack up to analysts' expectations in the second quarter, rising by only 1.8 percent — half the analyst estimate — and it remains in the midst of a multiyear turnaround effort. Newer burger darling Shake Shack has been pummeled. Shares are down more than 40 percent in the past year, and its latest earnings report after the close on Wednesday led to shares being slammed again. Same-store sales growth was one-third of last year's level, and average weekly sales were flat. Shake Shack isn't expecting same-store sales to improve over the rest of the year, either.

Which fast-food burger do you think is America's best?

Make your fast-food aficionado voice heard with a yea or nay. At the end, you'll see how all the burger chains are stacking up across every burger lover's votes.

Is a burger bubble near?

Warren Solochek, president of market research firm NPD Group's Foodservice Practice, said the lack of growth in visits to quick-service restaurants has persisted over the past four to five years. Visits to hamburger restaurants were up by 1 percent, while servings of burgers ordered were down by 1 percent in the past year. "It's probably not oversaturated yet, but I would say we are quickly approaching that point where the supply of restaurants, the supply of hamburger restaurants, is going to outstrip demand. And that's when the bubble bursts," Solochek said. BurgerFi's Lieber said it does concern him. "I think the difference between BurgerFi and the other brands is we really, really, really focus on families and millennials, but families in particular," Lieber said, pointing to its introduction last year of healthy kids meals. Offering healthy options isn't a guaranteed defense, Solochek said. "I think it's differentiating that group of chains as a whole from the established quick-service burger guys," he said. "Whether each one of them is differentiated from each other, I'm not sure."

Some of the most successful fast-food chains in the country are overlapping each other's traditional menu territories as they seek growth.

Chipotle is betting that the traditional burger model just needs an update. Its first Tasty Made burger restaurant is set to open this fall. "We think there's great strength in that original fast-food model," CMG Group CEO Steve Ells said in a statement. Solochek said the million-dollar question will be whether Tasty Made can differentiate its offerings from other fast-casual burger chains. Its first location isn't even open and it's already struggling to do just that with its logo and trademark.

Burger King is rolling out its Tex-Mex version of The Whopper, the Whopperrito, nationwide. The launch comes after the chain's second-quarter same-store sales missed analyst expectations by a wide mark.

"I think what the fast-casual players are doing is, they are forcing the older, larger brands to change their menu," Solochek said. There's an even bolder business strategy for rethinking reliance on the burger. Inspired by European and Canadian fry platters (known as poutine), French Fry Heaven loads up fries, potato chips and baked potatoes with toppings that range from taco fixings to shepherd's pie and breakfast favorites.



Loaded Spuds Cheeseburger platter at French Fry Heaven Source: French Fry Heaven