Preparation / Directions:
It is best to take large or small sprats, or, failing that, take anchovies, or horse mackerel, or mackerel, make a mixture of all, and put into a baking trough. Take two pints of salt per peck of fish and mix well so that fish are impregnated with salt. Leave it for one night, and then put in an earthenware vessel which you place, open, in the sun for two or three months, stirring with a stick at intervals, then take it, cover it with a lid, and store away. Some people add old wine, two pints per pint of fish [to the fish at the beginning of the fermentation process]. Drain the resultant sauce and store until use.
[Modern day nuoc nam is made by putting a layer of fish in a vat, adding a layer of salt, and repeating the process until the vat is full. After a few days the liquid is drained off from below and tipped back onto the top of the heap; this process is repeated several times. Finally, a wicker lid is placed on the vat and weighted down, and the fish are left to ferment and mature for several months. The resultant sauce is then drained and bottled as nuoc nam].
It can also be made from most any type of shellfish. If fish are smoked prior to salting, it should be a very light smoke so as not to dry the fish out or otherwise impede the fermentation process.