From fans getting tattoos of the bottle and personalising car number plates after it, to astronauts on the International Space Station taking it into orbit, never has there been a condiment with such a loyal fan base. Heat seekers are known to add it to almost any dish – drizzling it on pizza and sushi; mixing it into bowls of pasta or pho.

Easily spotted on the tables of Asian restaurants in the West, it is a common misconception that the “rooster sauce” – with its bottle covered in traditional Chinese characters and Vietnamese writing – is made in Asia. It’s also not produced by a Thai: the spicy sauce owes its success to soft-spoken Chinese-Vietnamese refugee David Tran.

“Americans don’t realise it is actually made in America. And that’s why I wanted to tell the story,” says Hammond, who went on a journey across two countries to make a documentary about the American-made hot sauce.

Huy Fong’s sriracha hot sauce is made in a factory in Irwindale, California. Tens of millions of bottles fly off its conveyor belts every year, yet demand often outpaces supply.

Tran left the country of his birth in 1979, at a time when people of Chinese ancestry were being persecuted in the wake of the Sino-Vietnamese war.

He and his family sailed on a freighter called the Huey Fong bound for the British colony of Hong Kong. The ship spent 30 days in Hong Kong waters before the colonial authorities allowed it to dock; the Tran family were later given asylum in the US.

 When they first arrived in Boston, Tran missed the food from home, like many immigrants at the time, and struggled to find fresh chillies. When his friend told him they grew in California, he moved with his family to Los Angeles.

“He just needed a job and found this niche where lots of Vietnamese immigrants in LA wanted hot sauce. So he started making the sauce and people liked it. He was pouring it by hand into glass bottles and delivering it personally [across California in his blue Chevy van],” says Hammond, who spent time with Tran at his factory while filming his 2013 short documentary, Sriracha.

What started in 1980 as a one-man operation on the outskirts of LA’s Chinatown soon grew into the empire it is today. Now in his 70s, Tran still oversees the US$80 million business named after the freighter which carried him on the first stage of his new life.

“I had nothing when I came to America. I had my wife and children to look after,” Tran says. “I saw peppers and I started making the sauce. All I needed was US$2,000 a month. But I earned more than [that] in my first month. I did nothing special but make chilli sauce. What I got was way beyond what I have ever asked.”

Huy Fong Foods also produces sambal oelek, a spicy paste, and chilli garlic sauce, but its sriracha is still by far the biggest seller, with the factory churning out 12,000 bottles an hour to keep up with demand.

This is quite a feat for a company that has never bought advertising for its products, instead creating a food empire based solely on word of mouth. This has not stopped diehard fans creating dozens of their own adverts and songs dedicated to their favourite hot sauce on YouTube.

While Huy Fong’s product is the most recognisable sriracha sauce in the West, it is by no means the only one on the market, nor was it the first. “Sriracha” is a generic name for a Thai hot sauce believed to have originated in the beachside town of Si Racha, on the east coast of Thailand.

There are numerous brands selling their own version of sriracha sauce in Thailand and, like ketchup, the flavour varies. But at its core sriracha contains chilli peppers, vinegar, garlic, sugar and salt.

“Some sriracha sauces are sweeter, some are more spicy, some are more sour. It depends on the producer,” says Titima Runguphan, founder of the Thai Culture Association in Hong Kong.

The Si Racha district of Chonburi province is known for its chillis and seafood, Titima says. And Thai people love to tuck into fresh seafood served with a healthy dash of sriracha on the side, or an omelette over rice that’s smothered in it.

It is unclear who invented the much-loved sauce, but one of the country’s most popular variants, Sriraja Panich, brands itself the “original” sriracha sauce.

Sriraja Panich was invented in 1949 by a woman named Thanom Chakkapak. The story goes that she made it for friends and family in Si Racha using local chillis and garlic, and so named her product after the town. Seventy years later, Sriraja Panich is owned by food company Thaitheparos.

To a connoisseur of Huy Fong’s variant, Sriraja Panich will taste slightly sweeter, less spicy, and have a thinner consistency than the American favourite – but that’s the way the Thais like it.

“[Huy Fong’s sriracha] doesn’t have layers. Thai people, we emphasis layers of taste; you have to have sweet, you have to have sour and you have to have saltiness … to suit the Thai taste. So maybe [Huy Fong’s spicy sriracha] … is suitable for Chinese people or Westerners, but for Thai people they would prefer the Thai recipe,” Titima says.

While there is much debate as to which brand can lay claim to the tastiest sriracha sauce, one thing is for sure: if you live outside Thailand, you’re probably pronouncing its name incorrectly.

Sriracha has three syllables: see-RAH-cha. The first ‘R’ in sriracha is silent. “Although we spell it with an ‘R,’ it is not pronounced because it is something in Thai language that we call a false cluster,” Titima says.

Hammond travelled to Si Racha on his journey to discover the origins of the hot sauce, and says locals were amused to find that a version of it was so popular in the US.

“There’s a common misconception in many places outside the US that Americans don’t like hot things. And so people in Si Racha were surprised to hear that sriracha, the namesake of their town, could be popular across the ocean,” he says of the sauce, which he uses daily.

As for Sriraja Panich, while he is a fan, Hammond is not going to be changing his hot sauce allegiances any time soon. “Yes, [Huy Fong’s sriracha] is still a better sauce for my American palate, I suppose,” he says.

Back in America, Huy Fong Foods remains a family-run business, with Tran’s son the company’s president and his daughter its vice-president. Despite his success, Tran has no plans to cash in on his good fortune.

“My dream is fulfilled. I don’t want anything else,” he says. “My goal was never to make money. I asked for little. Do not do things for the money; you won’t succeed.”

As for why there is a rooster on the front of the bottle, it is because Tran was born in the Year of the Rooster, according to the Chinese zodiac – a bold symbol for a man behind one of America’s boldest sauces.

Additional reporting by Yang Yang