Fish sauce. It's such an unfortunate name. If I was renaming it I'd call it "essence of the sea". But even that falls short. It's composed of just fish, salt and water. In Vietnam fresh fish, often anchovies, are fermented along with sea salt in huge wooden barrels and the resulting liquid is somehow not as salty as soy sauce but clean and fresh tasting with the essence of fish but with no "fishy" flavor. The taste is pure umami, that fifth flavor of savoriness. Visiting fish sauce factories in Phu Quoc, I was struck by the scent of the sauce which was sweet, salty and very pungent but not unpleasant.
Some of the most desirable fish sauce is made on the island of Phu Quoc (and also Phan Thiet). The first extraction called nhi is poured off after many months. More salt and water (sea water) is added and it continues to ferment. This process is repeated several times over the course of a year. The first batch is the best quality and contains the most protein. Following batches have less. The protein levels in these sauces range from 25-40%.
Like using anchovy paste, a splash of nuoc mam rounds out flavor without adding a fishy taste. It is used in Vietnamese recipes and as a dipping sauce when mixed with chiles, sugar, and lime juice. I found just a teaspoon or two in a bowl of pho makes all the difference. A good guide to purchasing Vietnamese style fish sauce in the US is available online at Viet World Kitchen.
FOOD + VIETNEM