Anchovy sauce and fish sauce are not the same product, but they’re close relatives. Both are made by fermenting fish with salt, and anchovies happen to be the most common fish used in fish sauce production across Southeast Asia. The confusion makes sense: the ingredients often overlap, but the names refer to distinct products with different origins, textures, and flavor intensities.
Where the Overlap Comes From
Fish sauce is a broad category. It’s a brown, salty liquid made by fermenting fish or seafood with over 20% salt, and it shows up across Thai, Vietnamese, Korean, and other Asian cuisines. The specific fish varies by country. Thai and Vietnamese producers frequently use anchovies, but Korean versions often rely on sand lance, and Taiwanese fish sauce may come from mackerel or milkfish. So while many bottles of fish sauce are technically made from anchovies, the label says “fish sauce” because the category isn’t defined by a single species.
“Anchovy sauce,” on the other hand, usually refers to a product that specifically highlights anchovies as the defining ingredient. The most well-known version is Italy’s colatura di alici, a golden liquid from the Amalfi Coast made exclusively from local anchovies and sea salt. Korean cuisine has its own version called myeolchi-aekjeot, a fermented anchovy product used heavily in kimchi making. In the UK, “anchovy sauce” sometimes refers to a thicker, spiced condiment with additional flavorings.
How They’re Made Differently
The basic process is similar for both: layer fish with salt, let enzymes and bacteria break down the proteins over time, and collect the liquid. But the details diverge in ways that affect the final product significantly.
Southeast Asian fish sauce is typically fermented for about a year in large vats. The result is a thin, dark amber liquid with a potent, funky aroma that mellows into deep umami when cooked. Italian colatura takes much longer. Producers in towns like Cetara pack hand-filleted anchovies into small chestnut barrels with Sicilian sea salt and age them for up to three years. When the sauce is ready, it’s drained through the layers of fish from the bottom of the barrel, filtering naturally through the anchovies for one last concentration of flavor.
Korean anchovy sauce follows yet another path. Whole anchovies are packed with 20 to 30% salt and fermented naturally for two to three months at around 20°C. Unlike the purely liquid Southeast Asian style, Korean myeolchi-jeot often retains a semi-solid or paste-like consistency from whole-fish processing. Some regional versions incorporate chili powder or garlic, though traditional recipes stick to just anchovies and salt.
Flavor Differences You’ll Notice
Glutamate, the amino acid responsible for umami taste, is the dominant flavor compound in both products. In Italian anchovy sauce, glutamate concentrations range from about 0.56 to 0.73 grams per 100 milliliters, with levels increasing the longer the sauce ages. A 48-month colatura has noticeably more umami depth than a 12-month version.
But umami isn’t the whole picture. Long-aged anchovy sauce develops surprising complexity: sweet, floral, and honey-like notes from alcohols that form during fermentation, along with fruity aromas from esters that emerge after years in the barrel. There’s also a cheesy funkiness from fatty acids like isovaleric acid, the same compound that gives cheddar its punch. Southeast Asian fish sauce tends to be more straightforwardly salty and savory, with a sharper fermented edge that works as a background seasoning rather than a finishing touch.
Korean anchovy sauce falls somewhere in between. Its extended natural fermentation produces pronounced anchovy-specific notes with strong umami, and the paste-like texture gives it a heavier presence in dishes like kimchi, where it also introduces beneficial microbes that support further fermentation.
Salt Content Varies Widely
Both products are high in sodium, but the range is broader than you might expect. Commercial fish sauces from four Asian countries showed sodium chloride levels between roughly 20 and 29 grams per 100 milliliters. Korean fish sauce runs the saltiest at around 29%, followed by Thai at 28%, Vietnamese at 24%, and Taiwanese at 20%. Italian colatura, while also quite salty, is typically used in smaller quantities as a finishing sauce, so the per-serving sodium hit tends to be lower in practice.
Can You Substitute One for the Other?
Yes, with some adjustments. America’s Test Kitchen recommends using half a teaspoon of fish sauce for every minced anchovy fillet a recipe calls for. This works best when anchovy is playing a supporting role, adding background umami rather than starring as a primary flavor. Going the other direction, you can use colatura or another anchovy sauce in place of fish sauce, but start with less and taste as you go. Colatura is more concentrated and complex, so a one-to-one swap can overpower a dish.
Worcestershire sauce is another option worth knowing about. It contains anchovies and tamarind, giving it a flavor profile that overlaps with both fish sauce and anchovy sauce. A few drops can fill in for either in a pinch, though the vinegar and spice base makes it a less precise match.
For kimchi specifically, Korean anchovy sauce isn’t easily replaced by Southeast Asian fish sauce. The paste-like texture, the microbial contribution to fermentation, and the concentrated anchovy flavor all play functional roles that a thin liquid sauce can’t fully replicate. One to two tablespoons of myeolchi-jeot per batch is standard in traditional recipes, often strained to remove bones before mixing into the kimchi paste.
How to Tell What You’re Buying
Labeling in the U.S. doesn’t draw a formal regulatory line between “fish sauce” and “anchovy sauce.” The FDA requires packaged foods to use either a legally specified name, the common or usual name, or an appropriately descriptive term. Both “fish sauce” and “anchovy sauce” qualify as common names for their respective products. The ingredient list is your most reliable guide: check whether the product contains only anchovies and salt, or a blend of fish species, or additional ingredients like sugar, hydrolyzed protein, or preservatives.
Products labeled “anchovy sauce” in Western grocery stores sometimes contain vinegar, spices, or thickeners that make them quite different from both pure colatura and Southeast Asian fish sauce. Reading the back of the bottle matters more than reading the front.