Nước chấm (Vietnamese: [nɨ́ək tɕə̌m]) is a common name for a variety of Vietnamese "dipping sauces" that are served quite frequently as condiments. It is commonly a sweet, sour, salty, savoury and/or spicy sauce.
Nước mắm pha (mixed fish sauce) is the most well known dipping sauce made from fish sauce. Its simplest recipe is some lime juice, or occasionally vinegar, one part fish sauce (nước mắm), one part sugar and two parts water. Vegetarians create nước chấm chay (vegetarian dipping sauce) or nước tương (soy water) by substituting Maggi seasoning sauce for fish sauce (nước mắm).
To this, people will usually add minced uncooked garlic, chopped or minced bird's eye chilis, and in some instances, shredded pickled carrot or white radish and green papaya for bún. Otherwise, when having seafood, such as eels, people also serve some slices of lemongrass.
It is often prepared hot on a stove to dissolve the sugar more quickly, then cooled. The flavor can be varied depending on the individual's preference, but it is generally described as pungent and distinct, sweet yet sour, and sometimes spicy.
People in the north of Vietnam tend to use nước mắm pha, as cooked by using the above recipes, but add broth made from pork loin and penaeid shrimp (tôm he). In the central section of the country, people like using a less dilute form of nước mắm pha that has the same proportions of fish sauce, lime, and sugar as the recipe above, but less water, and with fresh chili. Southern Vietnamese people often use palm sugar and coconut water as the sweetener.
Nước mắm pha is typically served with:
Vietnam—Nuoc Cham recipe (Chili, Garlic, and Fish Sauce). See http://www.globalgourmet.com/destinations/vietnam/nuoccham.html