Fish sauce

Fish sauce is a thin, amber liquid made by layering anchovies with salt and leaving them to ferment, often for a year or more. The fish breaks down and the liquid is drawn off. It is the main salty seasoning in Thai (nam pla) and Vietnamese (nuoc mam) cooking, much like soy sauce is in Chinese and Japanese food.

How to use it

• Add it during cooking to curries, soups, stir-fries and braises, a teaspoon or two at a time. It seasons and adds umami at once.
• Mix a dipping sauce: 2 tablespoons fish sauce, 2 tablespoons lime juice, 2 tablespoons sugar and 4 tablespoons water, with chopped garlic and chili. This is close to Vietnamese nuoc cham.
• Use a few drops in Western dishes too, such as tomato sauce, meat stews or Caesar dressing.

Fish sauce smells strong in the bottle. Cooked or mixed with sugar and acid, the fishy smell fades and leaves a rich savory taste.

Substitutes

• Soy sauce is the easiest swap. Use the same amount, or a little more, and add a squeeze of lime. The color will be darker and the taste less funky.
• Mashed anchovy fillets with a little water, about one fillet per ½ teaspoon of fish sauce.
• For a vegan version, mix soy sauce with a little seaweed soaking water or a pinch of salt and lime.

How to store it

An opened bottle keeps for a long time in a cool cupboard, but it darkens and gets stronger over the months. Keeping it in the fridge slows this down. Salt crystals at the bottom of the bottle are harmless.

Common mistakes

• Adding it like salt without tasting. Brands vary a lot in saltiness. Add a little, taste, then add more.
• Pouring it into a very hot dry wok, where it scorches and smells harsh. Add it with other liquids.

Fish sauce is made from fish, so it is not suitable for anyone with a fish allergy, and it is not vegetarian. Check the label of curry pastes, which often contain it.