Nam phrik type sauces are normally served on small saucers placed by the main dish as a condiment or dip for bland preparations, such as raw or boiled greens, fish, poultry and meats. Depending on the type, the region and the family that prepares it, nam phrik may vary in texture from a liquid to a paste to an almost dry, granular, or powdery consistency.
Instead of khrueang kaeng or phrik kaeng, the words nam phrik can also be used to denote Thai curry pastes such as in nam phrik kaeng som for kaeng som or nam phrik kaeng phet for kaeng phet.
The first Westerner to report of nam phrik was Simon de la Loubère, a French ambassador to the court of Ayutthaya. In 1687–88 he noted that it contains "a mustard like sauce, which consisted of crayfish corrupted (fermented fish); which they called kapi." King Chulalongkorn, regarded as one of the greatest kings of Thailand, repeatedly stated during his tour of Europe in 1907 that, besides khai chiao (omelette), he most missed nam phrik. The chef David Thompson, an acknowledged expert on Thai cuisine, writes, "They are at the very core of Thai cooking and have fed the Thai from their distant past to the present."
Types of nam phrik vary according to the ingredients, the preparation and the region. Some may include tamarind, green mango, galangal, lemongrass, and/or mushrooms and even ingredients such as frog. If fish paste is used, it may be made in a variety of ways, by mincing dried, boiled, grilled or salted fish, or by using fish roe. In Isan, pla ra, giving an intense flavor, is often used. Some types of nam phrik may be sweetened with sugar. A Thai cook book from 1974 lists over 100 different recipes. Among the most widespread varieties, the following deserve mention:
Nam phrik kapi (Thai: น้ำพริกกะปิ) is one of the most widespread varieties and is typical of central Thailand. It contains fermented shrimp paste, lime, chilies, and often pea eggplant. It is often eaten with fried pla thu and vegetables, among other dishes.
Nam phrik kha (Thai: น้ำพริกข่า) is made with roasted chilies, garlic, galangal and salt. This northern Thai specialty is often served as a dip for steamed mushrooms.
Nam phrik phao (Thai: น้ำพริกเผา) is sweetened with sugar and, among other ingredients, roasted chilies and tamarind. It is popular as a spread on bread or toast. It can also be used as an ingredient, for instance in tom yum or in the Thai salad with squid called phla pla muek.
Nam phrik pla ra (Thai: น้ำพริกปลาร้า) is made with pla ra as one of the main ingredients. Like most types of nam phrik, a little water is used if the mixture becomes too thick.
Nam phrik pla salat pon (น้ำพริกปลาสลาดป่น), also known as phrik pla salat pon, is a variety of nam phrik with powdered, roasted, dry pla salat (Notopterus notopterus). All main ingredients (the dry fish, red dry chili and garlic) are previously roasted until crunchy. Shrimp paste and sugar are also added, and the mixture is pounded with a mortar and pestle. It is eaten with raw vegetables, and is popular in Khorat.
Nam phrik pla yang (Thai: น้ำพริกปลาย่าง) is mainly minced, grilled fish, usually pla chon, mixed with onion, garlic, powdered chili, tamarind, shrimp paste, fish sauce and sugar.
Akkasit Jongjareonrak et al. Antioxidant activity of fermented fish viscera (Tai-Pla) from short-bodied mackerel, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, 90112 Thailand