Ildefonso Ramirez, a Cuban chemist-turned-Alabama sandwich shop owner after fleeing Fidel Castro’s regime, has died at 100, Kool Korner announced Thursday.

Ramirez, who perfected the Cubano — sliced ham and roast pork sandwiches with Swiss cheese, pickles, mustard and mojo sauce, served on a loaf of crusty Cuban bread — died just days before his 101st birthday.

Kool Korner, in Vestavia Hills, has closed its doors for the rest of the week following Ramirez’s death.

As a young man, Ramirez earned a chemistry degree at an institute in his hometown of Matanzas on the northern coast of Cuba, and then he went to the University of Havana to study medicine and become a doctor. After his third year, though, he had to come home to help care for his dying father and, for financial reasons, never returned to medical school.

Instead, he found a job as a chemist at a rayon factory in Matanzas, where he worked for nearly 20 years. He and Lucia, who had sent him packages of food while he was away at medical school, got married in 1951. Their son, Guillermo “Bill” Ramirez, was born in 1957.

But after Cuban revolutionary Castro overthrew the Batista dictatorship and subsequently converted the country to communism, Ramirez — who had first believed Castro to be a conquering hero — started making long-range plans to get out of the country.

When Bill Ramirez was a little boy, he was already starting to learn English by reading his father’s Dennis the Menace comic books and Popular Mechanics magazines.

“The decision to leave the country was because of me,” he told AL.com in a 2016 feature story on his father. “He did not want me to have to grow up in communism. So my parents both decided to leave their parents and their brothers and sisters behind to take me out of there.”

When the Ramirez family arrived in Miami, Ildefonso Ramirez, who was about to turn 50 years old, struggled to find work as a chemist.

Instead, he went to work in a friend’s grocery, unloading trucks and stocking shelves.

Ildefonso Ramirez later convinced his friend that they should start selling Cuban sandwiches, and he taught himself how to make them.

Meanwhile, Bill Ramirez was accepted to Georgia Tech University in Atlanta, and his parents decided to move there to be closer to their son.

That’s where Ildefonso Ramirez bought a store called Kool Korner Grocery, in Atlanta’s Midtown district, in 1985.

Gradually, word got around about Ildefonso Ramirez’s authentic Cuban sandwiches, and Tech students and Midtown office workers started lining up at lunchtime. With only a couple of chairs inside, they ate their sandwiches while sitting at the picnic table out back or on the concrete wall across the street.

For several years, the Kool Korner’s Cuban sandwich won “Best of Atlanta” awards from Atlanta Magazine, and Garden & Gun magazine later included it on its list of “100 Southern Foods You Absolutely, Positively Must Try Before You Die.”

One day, though, after they had closed for the day, Lucia Ramirez told her husband she wasn’t feeling well, and he said they should go to the hospital. She told him she couldn’t go without taking a shower and changing clothes first.

Several minutes later, Mr. Ramirez found his wife on the floor of their bedroom, dead of a massive heart attack. She was 81.

“He was devastated,” Bill Ramirez says. “He blamed himself. He thought his world had ended.”

A month or so after his wife died, Mr. Ramirez went back to work.

“The store helped him get over his grieving,” his son says. “That’s what kept him going.”

Ildefonso Ramirez kept Kool Korner Grocery open another three years, until the building was sold in 2006.

Not long after, Mr. Ramirez decided to move one last time.

“I was alone,” he recalled in 2016. “I decided to come where my son was, and I came to Birmingham.”

He got bored staying at home alone, though, and on a trip Publix to get groceries one day, he noticed that the former Firehouse Subs space in the Vestavia Hills City Center was for lease.

Soon, with the help of his son, Ildefonso Ramirez was back in business.

And when they heard the news that Ildefonso Ramirez had reopened Kool Korner, many of his customers from Atlanta drove to Birmingham to have a Cubano with their friend, and to take some sandwiches back home with them.

“They wanted to go back and sit with their sandwiches, eating their sandwiches on the ledge, where they used to sit,” Bill Ramirez says.

At age 92, Ildefonso Ramirez came to another crossroads when his lease expired at the Vestavia Hills City Center.

The rent was going up, his son says, so he and his father decided to close the sandwich shop. But there was never any question that he wouldn’t reopen it.

“Not even a chance,” Bill Ramirez says. “He was looking for a new place immediately. We were going up and down (U.S.) 31 looking for a place.”

It took several months for Ildefonso Ramirez to find a new space.

After Ildefonso Ramirez turned 93 years old, Kool Korner Sandwiches was brought back one more time.

The sandwich shop moved into its new location at 1360 Montgomery Highway in the Vestridge Commons retail center, a few doors down from Sol Azteca Mexican restaurant.

The mystery ingredient in Mr. Ramirez’s Cubano is the garlicky marinade he injects into the pork before it goes into the oven.

The recipe is a closely guarded secret that even his son doesn’t know.

But Ildefonso Ramirez told AL.com that he promised to pass it along in his will.