(Thai) Fish Sauce – Nahm Bplah
by Kasma Loha-unchit
Virtually every Thai recipe uses fish sauce. In addition to the information on this page, check out these three feature articles about this most important of all Thai ingredients:
- How Fish Sauce is Made – Made from fresh fish from the sea fish sauce does wonders for Thai food.
- How to Flavor Food with Fish Sauce – From its Mediterranean Roots, fish sauce now flavors all sorts of Southeast Asian foods. Recipes for three sauces included.
- A Visit to a Thai Fish Sauce Factory.
Fish Sauce (Nahm Bplah): The single, most important flavoring ingredient in Thai cooking is none other than fish sauce – the clear, reddish brown liquid made from fresh fish from the sea. Used like salt in western cooking and soy sauce in Chinese cooking, good-quality fish sauce imparts a distinct aroma and flavor all its own. It is indispensable in the Thai kitchen, as Thai food wouldn’t be quite the same without it. Fish sauce complements seafood dishes especially well and is used in just about every recipe in this book.
Called nahm bplah, or literally “fish water,” genuine fish sauce is the water, or juice, in the flesh of fish that is extracted in the process of prolonged salting and fermentation. It is high in protein (as much as ten percent), and this protein is a complete one containing all the essential amino acids that the body requires for growth and regeneration. Top-quality fish sauce also contains a rich supply of B vitamins, particularly B 12, Pantothenic acid, riboflavin and niacin. Other beneficial nutrients include calcium, phosphorous, iodine and iron.
Because good fish sauce adds a delicious dimension to Thai food, it is important to know how to select from the myriad brands sold in Asian markets. Just as there are many grades of olive oil that can make a big difference in the quality of the Italian dishes you cook, there are many grades of fish sauce that can make your Thai dishes vary from simply acceptable to exceptionally flavorful. But unlike olive oil, even top-grade fish sauce is quite inexpensive and affordable. A standard 24-fluid-ounce bottle of premium quality fish sauce costs under $3 in Asian markets. Therefore, it is good to know how fish sauce is made, what makes for different grades, and what characteristics to look for in making your choices from among the many brands available in the markets near you.
Though most fish sauce today is made from saltwater fish, it can also be made with small freshwater fish, as used to be done extensively in the past before pollution and dams drastically reduced the once plentiful supply of freshwater fish. A limited quantity is still produced in a few areas in the vast, wet flatlands of Thailand’s central region, traversed by several major river systems and an endless maze of canals.
Whether freshwater or saltwater, fish for making fish sauce are usually small ones that otherwise would have little value for consumption. Among the most common marine fish used are anchovies and a few related species of schooling fish, from two to five inches in length, found in bountiful supply in the rich gulf waters. Larger varieties of fish, such as mackerel and sardines, also make good fish sauce, but because they are relatively more expensive due to their value as a food fish, they are seldom used in the commercial production of fish sauce. For fish sauce to develop a pleasant, fragrant aroma and taste, the fish must be very fresh. As soon as fishing boats return with their catch, the fish are rinsed and drained, then mixed with sea salt – two to three parts fish to one part salt by weight. Large earthenware jars, or concrete vats, with a layer of salt on the bottom are filled with fish and topped with another layer of salt. A woven bamboo mat is placed over the fish and weighted down with heavy rocks to keep the fish from floating when their juices are extracted by the salt and fermentation process.
The jars are covered and left in a sunny location for nine months to a year. From time to time, they are uncovered to air out and to let the fish be exposed to direct, hot sunshine, which helps “digest” and turn them into fluid. The periodic “sunning” produces a fish sauce of superior quality, giving it a fragrant aroma and a clear reddish brown color.
After enough months have passed, the liquid is removed from the jars through a spigot on the bottom of the jars, or by siphoning. Any sediments are strained out with a clean cloth. The filtered fish sauce is put into clean jars and allowed to air out in the sun for a couple of weeks to dissipate the strong fish odors. It is then ready for bottling. The finished product is 100-percent, top-grade, genuine fish sauce.
Second- and third-grade fish sauces are made by covering the fish remains with salt water, letting the mixture sit for two to three months, then filtering before bottling. Finally, the fish remains are boiled with salt water, then strained out and discarded, to produce the lowest grade fish sauce. Because flavor is substantially reduced with each fermentation, top-grade fish sauce is frequently added to the lower grades to improve their flavor.
Since natural fish sauce requires time to make and very fresh fish, substantial investment is necessary for large-scale production. This has resulted in the proliferation of a number of less-than-pure products. Some are made by hydrolysis, in which some kind of enzyme or acid is added to hasten fermentation, while others are made by diluting natural or hydrolyzed fish sauce with salt water flavored and colored with sugar, caramel, monosodium glutamate (m.s.g.), and other natural or artificial flavorings and coloring.
How can you tell which brands are good? Check the labels, though the certification of quality awarded by Thailand’s Commerce Department is not always translated into English. Ingredient lists and nutritional analyses cannot always be relied upon either. Short of being able to decipher or trust the labels, look for fish sauce with a clear, reddish brown color, like the color of good whiskey, without any sediments. If the color is a dark or muddy brown, the sauce is likely to be either a lower grade, or one that is not properly or naturally fermented; it may also have been sitting on the shelf a bit too long. After a bottle of fish sauce has been opened, it may darken in color as it is exposed to air without losing much flavor for some time, but when salt crystals or grit begin to form at the bottom of your bottle of fish sauce, it is surely time to throw it out and buy a new one.
Good fish sauce has a pleasant aroma of the sea, not an overwhelming smelly fishiness, and it should not be overly salty. If the bottle you have been using makes the dishes you cook taste too fishy, try a new brand. My favorite brands from among those available near my home in California, are Tra Chang (meaning “weighing scale”) and Golden Boy. The latter is favored by my students for its endearing label, showing a baby boy sitting on a globe, cradling a bottle on the left arm with right thumb up. Both are excellent, adding a superb flavor to Thai dishes. Reasonably good are the King Crab and Anchovy brands. Since the degree of saltiness varies from brand to brand, make adjustments as necessary in your cooking, adding just enough to salt the food to your liking. (See Cooking "to Taste".)
Finally, fish sauce does not need to be refrigerated after opening, unless you cook Thai very infrequently. Store with the lid snapped shut in a cool place in your cupboard and keep the cap snapped tightly as exposure to air can turn the sauce darker in color and evaporation can intensify its saltiness. If you use your fish sauce very rarely, salt will eventually crystallize on the bottom of the bottle, but it should still be fine to use. The sea salt in fish sauce preserves it indefinitely.
While fish sauce is the quintessential Thai flavoring agent, its origins can be traced way back to the days of the Roman empire, when an extract of anchovies from the Mediterranean, known as “garum” (or “liquamen”), was a cherished elixir used for flavoring the cuisines of those times.
Our Ingredients Index contains links to many more Thai ingredients.