Fish sauce is one of those things that on it's own could be considered pretty gross, but of course that is not how it is intended to be used. When used in a dish it adds amazing flavor. You have probably had it in dishes a million times, but just didn't know it. You would notice a missing flavor if those same dishes were made without it though.
I have found that, because I never want another quart bottle of patis hanging around my kitchen for months on end, it is best to go to a specialty store like Cost Plus World market, where you can buy fish sauces from several different southeast Asian countries, in very small bottles.
I think it is made from fermented anchovies, not packed in salt. It keeps literally forever at room temp. There have been articles that many top chefs are using it in many sauces just for that "mysterious something". I love it. The smell is NOThing like the flavor.
it is fermented, (after they squeeze the "sauce" out of whole fish ) but also has salt in it. some add other herbs and flavorings.
i wonder if the salt is used to control the fermentation, besides preserve it?
the less fermentation, the fishier it will smell and taste.
Just be careful when using it because the flavor can throw the taste of the entire dish off, depending on what other ingredients are being used, and especially if you're experimenting. Soy sauce is more versatile if you're looking to add saltiness to an Asian style dish, but you don't want to just add salt itself. However, in Southeast Asian cooking, if the recipe calls for using fish sauce then do not omit it. Like others have said, it is what rounds out the flavors of those dishes. If you want ideas on how it is used, and which flavors compliment it, look up some Thai and Vietnamese recipies so you can get a better idea of how fish sauce is used. Here is a starting point:
I looooooove fish sauce, and my favourite is Golden Boy. I am concerned tho' at the price. A measly .90cents for 750 mls. Less than a 500 ml Coke costs here!! So that sets me to wondering about just WHAT the workers at that Thai factory get in their pay packet. Now I feel bad. But I cant live without it. I will make my thoughts known to those that govern now that I think about it. Yessiree!
Try a slosh of fish sauce with your lamb roast and a little more in the gravy. Anchovies meld well with Lamb. I make various Asian influenced dressings with a little fish sauce added. A couple of sploshes in a Puttanesca sauce work well too. I f you want a subtle saltiness combined with a mere whiff of fishiness, then use this sauce. A Caesar dressing for eg, if you dont want/have anchovies. And of course, it is indispensible with Vietnamese cuisine, my new favourite food.
The French bottle it as well and calle it Sauce de Poison (sp). It is the same thing. Be careful as both Tat and Iron Chef have stated. Used in the right amount, it adds a wonderful flavor to many dishes. But use a litte too much and it can ruin the meal. It's like sesame oil that has been squeesed from roasted sesame seeds. A little goes a long way.