Secrets of America's Favorite Restaurants: DQ's Top Secret Sweet Tooth Testing

Sept. 14, 2010 — -- The science of sweetness is taken seriously at Dairy Queen, where research teams in white coats toil behind locked doors in search of a successor to the wildly popular Blizzard or Dilly Bar.

Stepping into a frozen version of Willy Wonka's factory, DQ's chief branding officer, Michael Keller, said the foundation of the fast-food chain – its soft-serve ice cream – is one of its most carefully-guarded secrets.

"There's no way I could tell you what's in that formula….it is kept in a safe deposit box and there are only a few keys to it," Keller told ABC News.

What DQ is more than willing to share are some eye-opening facts about the success of its expanded menu, which now includes burgers, fried chicken, and hot dogs. Lots of hot dogs.

So many hot dogs are consumed in a single year, in fact, that if they were placed end to end they would stretch from Earth to the International Space Station and back six times.

Then there are the now-famous Americans who once held their own behind the DQ counter, including former Attorney General John Ashcroft, lead singer Gwen Stefani of "No Doubt," actress Bonnie Hunt and country singer Martina McBride.

Inside the top-secret futuristic lab in Edina, Minn., where researchers seek the next great DQ frozen menu sensation, employees in white coats run tests on critical data to perfect the science of pouring special Strawberry Sundae sauce.

"For this particular test… we are looking for how it drapes on the soft serve so it looks inviting," Keller said.

The team appears to be striving for the sublime. Already, DQ says customers are happy enough with the Strawberry Sundae that the chain has to use 6.5 million pounds of strawberries a year.

It all dates back to 1938, when John Fremont "Grandpa" McCullough was experimenting with ice cream in Illinois. McCullough believed the treat was best enjoyed at 23 degrees, even though all other ice cream was sold at zero degrees.

Menu Adds Only After Taste Tests by 100,000

"(He) believed your taste buds literally froze, but at 23 degrees, the temperature at which ice cream comes out of Dairy Queen's freezers, you can taste all the flavors of the product," said Keller. "So they set about making a unique freezer that had never been made before where you could actually dispense semi-frozen ice cream, and thus was born the Dairy Queen soft serve and the Dairy Queen system."

Today, the international fast food chain serves 35 million customers every day. Some choose from the expanded meal menu, others stick with the frozen treats that have given DQ its trademark curl.

The secret soft-serve formula has spawned other novelty treats over the years, the most profitable of which is the Blizzard. First introduced in 1985, the half-malt, half-milkshake concoction quickly became DQ's best-selling item. There are now 100 blizzard flavors available.

Before any new product or flavor is placed on the menu, it's laboratory tested and tasted by some 100,000 customers and employees of Dairy Queen, which has been rebranding itself as DQ. The updated name was chosen by Dairy Queen as a reminder to customers that it serves more dairy products.

One of those customers is Warren Buffett – also DQ's owner – who gathers his family for a monthly trip to his favorite Omaha Dairy Queen. Like other customers, Buffet waits patiently in line deliberating what to order.

"I would recommend the Strawberry Cheesequake," said Buffett.

Buffett had his company, Berkshire Hathaway, buy DQ in 1998, sparked by a nostalgia for a taste that made him feel at home.

"I've been running a quality check for decades," said Buffett. "I like to buy things I understand. And I understand why people come to Dairy Queen, why I come to Dairy Queen. When I buy that I'm making a bet that 10, 20, 50, 100 years from now people will be doing the same thing. And so far it has worked out that way."