RALEIGH After 50 years of marriage and 45 years of owing a business together, Joyce and Groover Blitch have a simple recipe for success: love and coffee.

The couple run Raleigh’s oldest Dunkin’ Donuts franchise. While the Massachusetts-based chain has more than 7,000 franchised restaurants in the country, the Blitches’ Capital Boulevard store maintains the feel of a mom-and-pop diner with its swivel stools and sit-down counter service.

Their dedication to the store, which opened in 1967, and to each other has helped the Blitches build both a strong relationship and business.

“I always tell everyone we’ve really been married about 96 years because we’ve worked together for so long,” Joyce Blitch, 74, said. “Most people only have a half a day with their husband or wife.”

The couple had been married almost five years when they bought their first store. Groover Blitch was tired of sitting behind a desk as an engineer in Durham. Dunkin’ Donuts was starting to franchise and needed someone to run the new location outside of downtown. So the pair bought the shop, leased the land and moved to Raleigh.

And they didn’t think twice about working together.

“It had never crossed my mind that it was going to be a problem,” Joyce Blitch said. “Sure we get testy and uptight at times, but it’s never really seemed like a big problem. We may disagree on the way things are done, but the next day, one or the other wins.”

The Dunkin’ Donuts brand has grown since the couple’s early days, but the Blitches have maintained some of their old rituals. They still hand-cut their doughnuts as they did in the beginning and serve coffee from a 10-cup carafe, even as the company made the move to gallon pots to keep up with the demands of a high-volume pace.

“We do it the same way we did it 45 years ago,” Joyce Blitch said.

The Blitches have 12 full-time workers and three part-timers. And their employees are used to the couple’s give-and-take.

“My employees laugh because they can tell when I’m upset,” Joyce Blitch said. “He gets louder and louder, and I get quieter and quieter.”

The couple’s store is one of nearly two dozen Dunkin’ Donuts franchises in the Triangle. And being part of the chain means that the Blitches are limited in what they sell and how food is made, including throwing out the coffee every 18 minutes. However, the pair sets pricing on everything from employees’ salaries to food. The couple is also expected to adapt to Dunkin’ Donuts’ ever-changing technology.

“When we started 45 years ago, it was the old (cash) register … and everyone had to count change,” Joyce Blitch said. “Now… people don’t know how to count change, cause they don’t have to do it.”

At one point, the Blitches owned three Raleigh Dunkin’ Donuts, including stores on Wilmington Street and in Crabtree Valley Mall. They still own the Wilmington Street building and the land, but sold the Crabtree franchise in 2009 after owning it for 30 years.

Groover Blitch got his start in the doughnut business selling of all things Krispy Kremes. When he was a student at The Citadel in Charleston, S.C., the senior business major stocked a typewriter case with doughnuts and sold them to the other students.

Now, between working for Dunkin’ Donuts and working with his wife, the 73-year-old former Marine is used to having someone else call the shots.

“I say, ‘Yes, ma’am’ and ‘I’m sorry,’ ” Groover Blitch said. “And if we disagree on the way we think it should be done, it’s her call.”