Sriracha mogul David Tran is a 78-year-old immigrant turned multimillionaire—and now his empire is in peril

It took decades for David Tran to become a hot sauce multimillionaire, with his signature sriracha becoming one of the top three hot sauce brands in America.

He got started making chili sauce back in his homeland, right after serving in the South Vietnamese army and manning his older brother’s chili field to provide for his family. He would sell glass jars of the sauce door to door, Tran said during

He got started making chili sauce back in his homeland, right after serving in the South Vietnamese army and manning his older brother’s chili field to provide for his family. He would sell glass jars of the sauce door to door, Tran said during a 2013 interview for a Vietnamese American oral history project at the University of California, Irvine. He would do “nothing but take care of the chili and bring it to the market,” he recalled. It was a secretive operation, he said, because “at the time the communist[s] came and they closed almost every business because it belonged to the government.”

Tran and his family eventually fled Vietnam, bringing 100 ounces of gold stashed in cans of condensed milk to the United States, where he ended up in Los Angeles. There he forged an unlikely, decades-long bond with a California farmer nearly his same age as his main chili pepper provider.

But now, as Fortune’s Indrani Sen reports, Tran’s supply of the sauce that made him famous remains shaky despite reaching stores again after a spotty three-year run.

Beginning of a hot sauce empire

Arriving in Los Angeles in 1979, Tran was one of the more than 240,000 ethnic Chinese that left Vietnam after its long civil war ended in 1975. He rented an industrial bottling space near Los Angeles’ Chinatown in the 1980s, and named his company after the Taiwanese freighter ship that carried him away from Vietnam, the Huy Fong.

Tran initially expected sriracha to have limited appeal, explaining in his oral history that he initially thought he “was going to sell it to Chinese or Vietnamese.”

Tran didn’t spend a dime on marketing, but his product found fans across the country and was celebrated by chefs and celebrities like Miley Cyrus. The bottle could even be found on the International Space Station.

An unusual business model

Sriracha relied on just one red pepper grower: Craig Underwood, a fourth-generation California farmer who was struggling to keep up with Americans’ new taste for spicy and international food.

Underwood reached out to offer to grow peppers for the fledgling chili sauce company in 1988 and the two started a partnership that lasted almost 30 years. Tran and Underwood spent time with each other’s families, watched each other’s kids grow up, and even talked about succession plans.

The duo peaked at a harvest of 100 million pounds of peppers in 2015. Now that they’ve fallen out, all those years of friendship and chili peppers are water under the bridge.

This story was originally featured on Fortune.com