No, this is not turning into a food blog. But after writing about laap a few days ago, I got to thinking about one particular ingredient used in that dish that might but somewhat unfamiliar to Western diners but is nonetheless a fascinating substance: fish sauce.
My interest in the subject was first piqued by a book I recently finished, Catfish and Mandala, by Andrew X. Pham. It's a memoir-style travel tale about the author (a Vietnamese American), his family, and his return to Vietnam to cycle the length of the country. He was born in the city of Phan Thiet, which he identifies as one of the major fish sauce capitals of the world. More intriguing, though, were his references to the condiment when describing his heritage. Apparently, Vietnamese expatriates (called Viet kieu) who return to visit the motherland are not always highly looked on by those who never left. Pham has a hard time convincing the people he encounters that he is in fact Vietnamese and not Japanese or Korean. In his attempts to do so, he often tells them he is "full-blooded Vietnamese, pure undiluted fish sauce."
Having always assumed that fish sauce must have originated in China or Thailand, I was surprised to learn of its Vietnamese roots. After further research, it appears that many Southeast Asian cultures probably developed some variety of the sauce independently. In fact, the ancient Romans quite liberally used a condiment called "garum," very similar to modern Asian fish sauce. But regardless of all this, the Vietnamese seem to feel the most intimate connection to the stuff.
Fish sauce has been a vital source of protein and a staple part of the Vietnamese diet for centuries. Pham even describes how in the past it functioned as currency in his hometown. Called nước mắm, it is used to add saltiness to most dishes and can also serve as a dipping sauce. It can be made with pretty much any species of fish, but anchovies are most frequently used due to their omnipresence in the South China Sea and the fact that they're not in demand for consumption. Salt is added to the fish and they are placed in wooden boxes and allowed to ferment, sometimes for up to a year. The anchovy layers are slowly compressed, much like apples in a cider press, and the resultant liquid becomes fish sauce. Simple as that. Of course, the taste and quality can vary greatly depending on the duration of fermentation, the type of fish, and any other ingredients that are added.
According to one website I found, Vietnam sold its fish sauce worldwide up until the U.S.-induced trade embargo in 1975. It was 20 years before the country would reenter the fish sauce market, and apparently Thailand took advantage of the situation during that time to develop something of a monopoly. I'm not sure how accurate this description is, but it's certainly true that the fish sauce sold at grocery stores here invariably comes from Thailand.
As a final note, it's worth pointing out that vegetarians have a hard time finding a substitute for the unique flavor of fish sauce. I prefer the real thing but recently had cause to play around with concocting a fish-free replacement. What I did was boil some dried kelp (the thick kind, like you see in miso soup) in a pot of water--the longer the better, so that you end up with a stock with that very "oceany" taste. I then added some soy sauce and extra salt, let it boil a little longer, and that was it. After removing the kelp strips, it looked just like fish sauce, and the taste wasn't far off either. Of course, I don't have pure, undiluted fish sauce running through my veins, so maybe I don't know any better.