If you want to stock your kitchen with the bare minimum for preparing Vietnamese food, start with good quality fish sauce (nuoc mam). How do you judge fish sauce? Look for a light amber color and the words nhi or thuong hang on the label.
These terms indicate that the condiment came from the first extraction of liquid from the fermented fish, and is of the highest quality. Grades of fish sauces are similar to that of olive oils. That is, extra virgin olive oil is more flavorful and costlier than virgin olive oil. This same rule applies to judging different fish sauces.
Also keep in mind that fish sauce is also used in Thai and Filipino cooking, where it tends to be saltier and heavier in flavor. So, even though Thailand produces most of the fish sauce sold in the U.S., you need to make sure that the condiment you’re buying is made in the ‘Vietnamese’ style. How to do this? Look for Vietnamese lettering alongside the Thai script.
Sometimes, the terms Phu Quoc and Phan Thiet are included on the label to signal a connection with these two famous fish sauce-producing areas in Vietnam. Fish sauce from Vietnam now sometimes use "Hon Phu Quoc" or "Hon Phan Thiet" (see image on left) to indicate that their product came from islands in those regions; hon means islands, and communicates a more authentic Viet condiment (versus a Thai product, which may not be clued in on such linguistic subtleties).
About five years ago, One Pigeon brand from Vietnam offered different grades of fish sauce, using degrees on its labels to reflect how much the nuoc mam has been diluted with water before bottling. For example, "25° dam" means there's 25% fish sauce in the bottle. When I contacted the producer, he said that most fish sauces are 20%. One Pigeon came in several intensities. The higher the degree, the more you paid. That's how it is in Vietnam. Sadly, that fish sauce didn't last in the U.S.
If ca com is one of the ingredients, that's an indication that the end product was made from a high quality anchovy native to the waters surrounding the island of Phu Quoc. Though I like Viet Huong’s "Three Crab" brand for its consistently delicate flavor, aroma and color, I often try newer brands. Please note that Three Crabs and Flying Lion are both made by Viet Huong. The former is lighter in flavor than the latter, according to the Chung family that produces it.
Some are saltier while others are sweeter. Let your palate be your guide. Depending on where you shop, there may be as many as a dozen brands to choose from. As price is often a reliable indicator of quality among Asian groceries, select a mid to high priced fish sauce (about $3 to $4 per bottle!). If you buy online, fish sauce will cost a little more.
Hot to shop for fish sauce:
- Shop price -- choose mid to high price.
- Buy glass over plastic bottles as glass indicates a better quality product.
- Look for Vietnamese style fish sauce which is lighter in flavor than Thai nam pla or Filipino patis.
- Fish sauce with an amber-red color is better than dark coffee.
- Reliable brands I stick with: Three Crabs Brand Fish Sauce and Flying Lion; both are made by Viet Huong. Both are sold at Asian markets. If they're not available, use Tiparos Thai Fish Sauce or Thai Kitchen.
- Transport fish sauce standing up in your car, lest it leaks a bit; the bottles are seldom well sealed.
How to store fish sauce:
- If you use it often, keep it in a dark cupboard.
- If you seldom use it, refrigerate it where it will keep for months.
How to use fish sauce:
- You can always add more but it's harder to take it out of foods.
- I combine fish sauce with salt in cooking foods because the savoriness of fish sauce isn't the same as salt.
- Old school Vietnamese cooks use lower quality fish sauce for cooking and reserve pricier fish sauce for dipping sauces. If you can afford it, and I hope you can, use only the good stuff. Your food will taste consistently good.