Ingredient guide

Fish Sauce

Quick Answer: Fish sauce is a fermented seasoning made from anchovies and salt, aged 12–24 months. It is the primary salt source in Vietnamese and Thai cooking. Vietnamese fish sauce is graded by nitrogen content from 25°N to 43°N: higher numbers mean more protein, deeper flavour and higher price.

Key facts

  • Made from 2 ingredients only: anchovies and salt — anything else on the label is an additive
  • Vietnamese grading runs 25°N to 43°N nitrogen; 35°N and above is considered first-grade for dipping
  • Phú Quốc is a protected designation of origin in Vietnam, similar to Champagne in France
  • Salt content is roughly 20–25% by weight, so it seasons and salts simultaneously
  • Aged 12–24 months in wooden barrels; cheaper bottles are often diluted with water and caramel colour

What to look for when buying

  • Read the label: first ingredient should be anchovy extract, not water or sugar
  • Look for the °N number — 35°N+ for dipping, 25–30°N is fine for cooking
  • Dark amber is normal; a very dark opaque colour usually means added caramel

Substitutes that actually work

Instead of fish sauceUse
—Soy sauce plus a squeeze of lime (vegetarian, but misses the fermented depth)
—Thai nam pla — interchangeable in most recipes
—For vegan: fermented soybean or mushroom-based fish sauce alternatives

Used in these cuisines

Recipes using fish sauce

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Know what you're buying before you buy it

Every ingredient guide is written from what is actually on shelves in Vietnam, not from a translated list.