A key ingredient in the cuisine of Southeast Asia, fish sauce is a condiment made from the liquid of fermented fish (usually anchovies). The light-brown liquid is quite pungent and salty, and a small amount can wake up otherwise bland dishes with vibrant, savory flavor.
Known as nam pla in Thailand and nuoc mam in Vietnam, fish sauce is also a popular flavoring and table salt substitute in Burma, Cambodia, Laos and the Philippines.
There's good evidence that fish sauce came to Asia from the Roman Empire, where it was first made centuries ago. Called garum, the Romans fermented fish in brine for several days under the sun and then flavored the resulting liquid with oil, wine or spices.
While many grocery stores carry fish sauce, brands vary greatly in quality and flavor. Authentic imports have a richer taste and are more likely found in Asian specialty markets. Wherever you shop, base your selection on these two factors: clarity and price.
Good fish sauce has a nice, translucent amber color, similar to brewed tea. Avoid brands that are as dark as soy sauce or cola.
When it comes to fish sauce, price reflects quality. Premium brands are pleasantly fishy and moderately salty, making them suitable for raw vinaigrettes and dipping sauces, as well as cooked dishes.
Keep it in the pantry, away from light and heat. The condiment has a long shelf-life, but replace it if it starts to darken.
Different brands vary greatly in strength and salt content, so use fish sauce with caution in your recipes. Start with a small amount and add more to taste. Never serve fish sauce straight up.
Once you have a handle on its distinctive flavor, experiment by adding a few drops to your tomato soup, pasta sauce, meat marinade, Caesar salad dressing or stir fry. Fish sauce is actually a secret, "go-to" ingredient employed by many Western chefs when their recipes are missing "that certain something."
For more traditional uses, try a simple Thai dipping sauce called nam pla prik. Just mix fish sauce with minced Thai chilies and use it as a topping for burgers or pasta. For a healthy Thai dressing, whisk a few drops of fish sauce with lime juice, chili peppers, sugar and garlic.
When fish sauce is not available, soy sauce is an acceptable substitute in most recipes.