Nuoc-mam is a Vietnamese liquid flavouring. Nuoc-mam is clear brown liquid with a cheesy smell and a salty taste. It is made from small fish, such as the clupeids (herrings and sprats). The whole fish are pressed into tubs, salted and tightly sealed, then left for 12 weeks when the liquid is drained off. Salting is heavy and other flavours may be added, e.g. caramel, molasses or boiled corn.
Petis and Nuoc-mam Roc are variations on the theme.
Dowell, P., Bailey, A. (1980) The Book of Ingredients, Dorling Kindersley. ISBN 0718119150.