(CNN) — Fish sauce – nước mắm, or literally ‘salted fish water’ – is a Vietnamese culinary icon, an indispensable national ingredient up there with olive oil or soy sauce.
But it’s fair to say that the production process isn’t the most fragrant, thanks to the sharp funk that comes from anchovies fermenting in huge wooden barrels for a year.
They’ve been around since 1950 and pride themselves on their reputation as one of the leading producers on an island that many Vietnamese believe is responsible for the best fish sauce in the country.
On the hunt for umami
The vast repertoire of beautifully executed Vietnamese dishes they serve, such as seafood and pomelo salad or lobster with stir-fried vegetables, is largely supported by the unique flavor profile and prominent umami – the ‘fifth taste’ or unique flavor – as offered by Phú Quốc fish sauce.
But for a taste of Vietnamese fish sauce, you don’t have to look far. It is present in pho, spring rolls, com tam, banh xeo, com thit nuong, and dozens of other ubiquitous dishes.
A Phung Hung employee guides visitors through the factory.
How the magic happens
The crucial ingredients in fish sauce are cá cơm (black anchovies) and smaller white anchovies. Together they make up about 95% of the fish used. Larger fish such as sardines and herring make up the rest.
Traditionally, fish were caught in the Andaman Sea around Phú Quốc, but today they mostly come from Tho Cho Island, about 70 miles away. They are only caught between April and September, which roughly corresponds to the rainy season.
Phung Hung has its own fishing boats, which allows them to oversee the entire production process. When the fish is caught, it is immediately drained while still on the boat, then salted and stored meaning the fermentation process has already started, using the freshest catch possible.
They use salt that comes from the southern coastal province of Ba Ria-Vung Tau and add it at a ratio of one part to four parts fish.
When the fishing boats land, Phung Hung employees collect the 200-kilogram (440-pound) containers of fish and mix them together in their own barrels.
Fish sauce vats used to be made by hand from wood from boi loi, a tree from Phú Quốc National Park, but is now so endangered that wood has to be imported from Cambodia. Some have compared the importance of the wood to aging wine in oak barrels, giving it its own unique flavor profiles.
The hefty barrels are made of 54 slats of wood, tied together by hand with rattan rope. It takes two men three weeks to make one.
Once the barrel is filled, the workers clamber out, don white rubber boots and begin to compact and press it down by stepping on the mix.
After that, every day for a whole year, the liquid that seeps from the fish is drained and returned to the vat — but the most important thing is that there is no stirring or mixing, as in the production of fish sauce in other provinces of Vietnam.
Workers check the contents and taste the sauce to decide when a batch is ready.
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Part of the secret of the sauce is Phú Quốc’s unique combination of environmental factors, including the right humidity and heat that allow the mixture to slowly reduce, leaving between three and four thousand liters of fish sauce per barrel.
The final stage comes when they send a sample of the sauce to the lab to get a degree of intensity measured in degrees of nitrogen, a byproduct of the fermentation process. Without the correct level, it cannot be certified on the bottle label.
The mildest version starts at 35° N, while the most intense is around 45° N.
Fish sauces from Phú Quốc — there are more than 70 different producers on the island — tend to have a higher nitrogen content, resulting in complex and different flavor profiles.
The first printing
If you’re looking for the most prized and expensive fish sauce, it’s pulled straight from the first pressing of a single barrel, undiluted and unmixed.
Look for the words “nước mắm nhi” on the label. That means it comes from the first extraction of liquid from the vessel. Some call it “extra virgin fish sauce.”
“Fish sauce is the national soul, the national essence of the Vietnamese people, which sets the country’s cuisine apart from the rest of the world,” says Anon. “A small bowl is central to every Vietnamese meal, a sauce that binds everything on the table together.”
He explains that here are several layers to taste.
“It would be too simple to say that fish sauce tastes like fish, or even salty. Quality blends have a salty, round taste that you can even taste straight from the bottle. Your mind can go to the taste of fresh fish or to sitting on the beach.
“Fish sauce sometimes has a hint of sweetness, a mineral flavor, or a hint of caramel.”
“This is killer.”