Fish sauce is an essential ingredient in much of both Thai and Vietnamese Cuisine. It needs to be there, as it imparts that certain, distinctive “something” – but I’m inclined to agree with the following opinion I found at http://forums.egullet.org:
“I have a love hate relationship with fish sauce. It’s got to be there, but I don’t want to know. Does that make sense? Without it, there’s definitely something missing. But if it’s strong enough that I recognize the taste, it’s too strong.
Translation of “too strong”: REEKS.
I had a Vietnamese friend some years ago, and his mother would prepare for us these elaborate meals comprising multiple dishes. Pho, crispy spring rolls, delicate soups with shrimp and barbecued pork to which chile sauce was added, some concoction of vegetables and quails eggs, rice cakes with savory pork, on and on…The house would smell heavily of fish sauce when she was cooking, but as the stink of the sauce gradually merged with the other ingredients, what at first had hinted of putridity was magically transformed to savory.
There was one particular dish, called “Tka” (I’m uncertain on the spelling, but it is pronounced Teh-KA) that stunk like a locker room in the first phase of preparation – which was simply the simmering of fresh pork in fish sauce. Phee-ew.
The final dish, however, was delicious – the pork was coated in a caramelized sweet sauce, which was then served on fragrant rice. And there, in the background, was that “certain something,” that hint of fish sauce. Lovers of Thai and Vietnamese cuisine will immediately identify with this: there is a certain savor, a kind of hard-to-describe “edge” that fish sauce adds. The dish would be left wanting without it.
Stinky things can be good, and fish sauce is not the only food which bears this out.
How is fish sauce made? This is the part that used to really gross me out, but I’ve grown more accustomed to it as I’ve grown older.
1.) Get ye some freshly caught anchovies, or some other small variety of fish (any fish can be used, but small, commercially insignificant fish are preferred over bigger, “food” fish).
2.) Add 2 to 3 parts salt to one part fish.
3.) Take a large earthenware jar. Put a layer of salt on the bottom, and then add the fish. Once the jar is mostly full, add another layer of salt on top, and then a piece of bamboo mat, and weight it down with a heavy rock, or some large, non-toxic object.
4.) Set jar out in an area that gets lots of sun, and leave it there for 10-12 months. On hot sunny days, it is well for the jars to be opened and exposed to direct sunshine, which helps to further “liquify” or “digest” the fish.*
5.) After the months have elapsed, siphon out the “essence of fish.” Strain through cheesecloth (to remove any remaining solids) into clean jars, cover them, and let them sit out for another week or so.
6.) Bottle it, and start using it. It’s fish sauce.
I don’t recommend trying this at home.
*Salt, sodium chloride, is a “hydrophilic,” or “water-loving” molecule. That is, it “wants” to bind with water. That’s why swimming in the sea dries your skin out. This is the essence of making fish sauce – the salt draws out all the natural juices of the fish, and prevents the growth of harmful bacteria at the same time, allowing a sort of controlled, aseptic and aerobic fermentation to occur.
In short, liquid fish.