nam pla (in Thai); nuoc mam (Vietnamese)
This pungent amber-brown liquid is a mainstay in Southeast Asian cooking. Known as nam pla in Thai and nuoc nam in Vietnamese, fish sauce imparts a distinctive salty flavor to many of the region’s dishes. Though its aroma is strongly fishy straight from the bottle, cooking mellows it considerably, as does combining it with other assertive ingredients, like lime juice, chile, and garlic.
Fish sauce is made from freshly caught fish that are too small for substantial eating, such as anchovies. The fish are packed between layers of salt in an earthenware vessel. A bamboo mat is placed over the final layer and topped with a weight to keepthe fish in place. They are then covered with an airtight top and set in a warm sunny spot where they are left to ferment for nine months and up to a year. As the fish break down, they produce a brown liquid—the fish sauce—which is drained from a spigot at the bottom of the container.
You can find fish sauce in most supermarkets, but an Asian market will offer more brands to choose from. As with olive oil, there are several grades of fish sauce. High-quality fish sauce, which is the first to be drained off the fermented fish, is usually pale amber, with a more delicate and balanced flavor; premium-grade fish sauce, such as Three Crabs or Phu Quoc brands, are best in dipping sauces. For cooking, stronger-flavored, lower-grade brands, such as Squid or Tiparos, which are made from a secondary draining, work fine. Fish sauces bottled in glass taste better and last longer than those packaged in plastic.
For cooking, you can use fish sauce straight, but never add it to a dry pan or the smell will be overpowering.
Refrigerated, it keeps for months; when it turns dark or crystallizes, discard it.