Le Thi Khuong doesn’t know exactly when the tradition of making fish sauce, nuoc mam in Vietnamese, took root in Ky Anh (Ha Tinh Province), her native place.

She only knows that for generations it has been the job of women and girls in the family to make it.

"My grandmother taught my mother, who then taught me how to make the sauce out of anchovies caught in the East Sea (internationally known as the South China Sea) and store it in ceramic barrels," Khuong told VnExpress International.

"The men - fathers and sons - would sail and fish, and when they returned, their wives and daughters would wait for them at the wharf with baskets in hand."

Anchovies caught and sold at a wharf in the south central province of Ninh Thuan.
Photo by Thanh Nguyen.

The catch would be sorted and sold, except for anchovies deemed too small to induce any flavor in cooking. Fermenting it with salt, the ancestors discovered, was the best way to juice out the fish’s nutrition and savor its taste.

The process of making nuoc mam usually starts between December and April, during the "anchovy season." The salt used must by then have been stored for at least two years, "to dry out the acrid taste, before it is mixed with the fish at one to four ratio," Khuong said.

The mixture is compressed, sealed in either wooden barrels or big clay jars and left under the sun for months. Every day, the liquid is siphoned out through a small tap at the bottom and poured back into the container right away from the top to ensure it zigzags through layers of the fermented fish and distills out all the nutrition.

The same recipe has been used for centuries, with small improvisations made in different places to adapt to the local weather or to create a locally distinctive taste.

While Khuong adds rice bran to color the liquid, in Van Phan commune, Nghe An, where the East Sea cut deepest into the Indochina Peninsular, dried sugarcane molasses (or brown sugar) or pineapples are used to enhance the sauce’s sweetness.

In the southern provinces, the salt and fish ratio is one to three as the hotter climate is believed to help the brew stew better.

A worker in Van Phan Commune, Nghe An Province, siphons out liquid from fish sauce barrels.
Photo by Nhung Nguyen.

Around a year later comes the precious, first extraction of the fermented liquid, nuoc mam nhi. Dubbed the "virgin fish sauce," this must have a reddish amber color, and when it touches the tongue, strike the taste buds at once with a burning saltiness, yet leave a sweet zest lingering after swallowed for a while.

"Just a drop of nuoc mam nhi can fill a house with its aroma," Khuong said. Salt water is then pumped into the barrels two to three times to distil the first, second and third grades of fish sauce.

Above all, nuoc mam nhi is considered to be of the best quality and hence most expensive.

"Although you can see a lot of cans labeled as the sauce on store shelves everywhere, the premium nuoc mam nhi is in fact rare and scarce," said Nguyen Thanh Loi, a historian of Vietnamese sea culture.

"It is usually not for sale, only used by the makers’ families or in the middle of the sea, for divers on fishing boats to balance their body temperature," said Loi, who teaches culture at the National College of Education in Ho Chi Minh City.

Before sonar instruments were invented to detect schools of fish underwater, Vietnamese fishermen relied on gifted divers to navigate for them. And these divers would sip nuoc mam nhi after every dive "to keep their bellies warm", Loi told VnExpress. "Because their role is so crucial for the catch, the best fish sauce was reserved for them, out of respect."

While the oldest trace of fish sauce in human history dates back to the Roman civilization, exactly when nuoc mam made its way into the Vietnamese cuisine is unclear. Some records indicate that it was more than a thousand years ago.

A traditional nuoc mam village in Ba Lang Commune, Thanh Hoa Province pictured in 1925.
Photo via Flickr/manhhai.

In 997, nuoc mam had already been required by China’s Song dynasty as a local tribute to be sent over from Vietnam. The act is mentioned in Dai Viet Su Ky Toan Thu, or Complete Annals of Dai Viet – a 15-volume work published in the 15th and 16th centuries, compiling and chronicling the history of the Viet people from 2879 BC to 1697 AD.

According to the book, in the first years of Vietnam’s independence from China, fish sauce and salt had become staples subject to taxes alongside land, rice and luxury goods.

A trade limitation was also placed on these items during the closed-door policy imposed against the Northern Empire whenever relations soured. In 1427, the last year of the Fourth Chinese domination of Vietnam, two Viet men were beheaded for engaging in fish sauce and salt trade with the "enemy", the Chinese from the Ming Dynasty then stationed in the northern province of Hai Duong.

"When the Westerners came in, nuoc mam set the locals apart from them," Loi said, referring to first European missionaries in the 16th century and the French colonizers who followed in the 19th and 20th centuries.

"You see, because of what they said was the unbearable smell, nuoc mam was never really popular among those foreigners, so then it was safe to say that whoever could savor the local fish sauce was recognized a true Vietnamese."

Fish sauce is the soul of the country’s cuisine today, adding complexity to cooked dishes or poured into a tiny bowl and placed next to the main course as a robust flavor sidekick.

It has also placed itself on the global food map. Most memorably, in his Parts Unknown episode on Hanoi in 2016, the late celebrity chef Anthony Bourdain showed his special guest, the then U.S. President Obama, how to relish bun cha, rice vermicelli with grilled pork by dunking it in the "ubiquitous nuoc mam."

Fish sauce is so ubiquitous in Vietnam that it has grown into a multi-million-dollar industry, valued at $501million by market researcher Euromonitor in 2015. The whole country consumes around 250 million liters of the sauce a year, or two liters per capita, according to the Ho Chi Minh City Food Association.

It was inevitable that such a staple commodity lured in the big fish.

Since the 2000s, many giant firms, locals and multinationals, hopped on the nuoc mam bandwagon by introducing their version of the sauce. Unilever, the British-Dutch transnational consumer goods company, Vietnam's Masan Group and food firm Acecook Vietnam were among the pioneers. The newest comer is Nestlé Vietnam, which unveiled in July 2018 a fish sauce cousin to its locally popular Maggi soy sauce.

The products introduced by the big companies has been dubbed "industrial fish sauce" or "dipping sauce" to distinguish them from the traditionally made sauce. The industrial fish sauce is a fusion of fish sauce, water, salt and additives such as flavoring, preservatives and food coloring. Hence this mixture is less salty, has a sweeter key taste, lighter color, and is less pungent.

With the waters getting more crowded, many traditional nuoc mam makers found themselves in a fierce and "imbalanced" competition, as Thanh Loi described it, with their market share narrowing.

Tellingly, around 70 percent of fish sauce consumption in the country, nearly 190 million liters, has been taken over by the industrial fish sauce, notably that of Masan, while around 2,800 traditional nuoc mam making villages and establishments scattered along the country’s coastline share the remaining 30 percent, or around 60 million liters, according to the Ho Chi Minh City Food Association.

"The industrial products seem to suit the modern lifestyle better," said Vo Van Dai, a traditional fish sauce maker in Van Phan, central Nghe An Province.

"People don’t have to mix it with vinegar and sugar and water to make it a dipping sauce, like in the old days. They just pour it out and serve. It’s more convenient."

It’s also cheaper. A traditional fish sauce bottle is usually one or two dollars more expensive than the industrial version, given the high input and production costs as well as low productivity.

Still, nuoc mam makers like Dai and Khuong like to believe theirs is the more authentic product with higher salt content and nitrogen levels, a result preservation by salting. The latter ingredient indicates grams of nitrogen per liter, so the higher the number, greater the protein content, and the stronger and more complex and piquant its taste.

Unfortunately, authenticity and potency have not helped the fish sauce makers in the market. In fact it was once used against them.

In 2016, a vague and misleading survey released by Vietnam Standards and Consumers Association (Vinastas) claimed nearly 70 percent of the 150 samples of traditional fish sauce taken from the domestic market had excessive levels of arsenic.

Almost immediately, the announcement triggered a widespread food scare across the country.

The health ministry quickly dismissed the finding, saying it failed to differentiate between highly toxic inorganic arsenic and safe-for-consumption organic variety found commonly in seafood.

Furthermore, the Vinastas study was neither independent nor objective, as it was sponsored by a major communication and advertising firm in Hanoi.

However, traditional fish sauce making and related industries had already suffered a consumer boycott.

"We had to stall our production, and so did many like us, from the north to the south, because few people dared buy from us," said Dai, recalling "the two week nightmare".

The crisis also unsettled some related industries, including fishing and seafood exports, and prompted outraged traditional fish sauce makers and associations, in a rare move, to unite and demand that the government "take proper actions" to ensure such dirty tricks do not happen again.

The “ubiquitous nuoc mam” is a indispensable sidekick of bun cha, or Vietnamese grilled pork vermicelli.

Despite this, thousands of traditional fish sauce makers are still struggling as their product keeps losing ground in the market.

Dai and Khuong are among the few who are proactively responding to the new challenges.

Khuong, with the support of rural development agencies, has adapted a closed/sealed fish sauce manufacturing system using solar energy to stew the brew.

The new technology has helped her reduce production costs and increase productivity, and overcome hygiene concerns usually associated with small facilities like hers. The longtime fish sauce maker is trying to keep her business running and providing a livelihood for over 40 workers, mostly women, keeping a legacy alive at the same time.

Meanwhile, Dai is working with other neighboring fish sauce makers to register Van Phan as a place of origin, like their peers on Phu Quoc Island who have established a brand with international renown.

In other words, Dai and friends are uniting to recover the ground lost and put Van Phan fish sauce back on the map. They are also eyeing the possibility of exporting their product, starting with Japan.

Asked why they don’t consider doing the same thing as their industrial competitors, and produce sauce with the same lighter and sweeter taste, both Dai and Khuong dismissed the possibility outright.

Dai asserted: "I sell nuoc mam, not a mixture."