Fish sauce

This type of sauce is used in one form or another throughout Southeast Asia. Although similar, varieties are not interchangeable. It is made from small fish or prawns (shrimp) that are salted and fermented in the sun for several months. Often the residue from this fermentation is used to make kapi (shrimp paste), the paste essential to Thai cuisine. Fish sauce is pungently salty and has a piercing aroma, but mellows when combined with other ingredients. There is no substitute, it is widely available and does not deteriorate.