Fish sauce and anchovies are doing two jobs: salt, and umami
Fermented fish sauce carries a lot of sodium: USDA data puts it at roughly 7,850 mg per 100 g, which works out to around 1,400 mg in a standard tablespoon, but the salt alone isn't why a splash of it deepens a soup or a dressing. Fermentation also breaks fish protein down into free glutamate and other amino acids, which is what actually reads as umami, the savory depth underneath the salt. Anchovies work the same way in a Caesar dressing or a puttanesca: salt plus glutamate-rich funk, melted into the sauce rather than tasting fishy on its own. A substitute that only covers the salt tastes thin. Covering both is the whole trick.
| Substitute | Covers | Ratio | Best for | Watch out for |
|---|---|---|---|---|
| Soy sauce or tamari | Salt, plus some umami | 1:1 by volume | Stir-fries, marinades, quick dressings | Missing fish sauce's fermented depth alone; pairs well with kombu or mushroom |
| Coconut aminos | Salt (noticeably less) and mild sweetness | 1:1, then taste and add salt | Soy-free cooking, lower-sodium recipes | Roughly half the sodium of soy sauce, so dishes can taste flat unless salted up |
| Kombu and dried shiitake soaking liquid | Pure umami, almost no salt | Use as the liquid base, salt it yourself | Broths, braises, dipping sauces | Not a quick bottled fix; needs time to steep or simmer |
| White miso, thinned with water | Salt, umami, and fermented funk | 1 tsp miso whisked into water per 1 Tbsp fish sauce | Dressings and marinades | Adds its own bean flavor; use a mellow white miso, not a dark red one |
| Store-bought vegan fish sauce | Salt and umami, formulated to match | 1:1 | Anywhere the original bottle was used | Brands vary in saltiness and funk more than most other swaps in this guide |
| Anchovies: white miso + capers or olive brine | Salt, umami, and brine funk | To taste, start small | Caesar dressing, puttanesca, tapenade | Capers bring a sharper brine note than anchovies; pull back other acid slightly |
Why kombu plus dried mushroom actually works, not just tastes okay
This isn't a folk trick. Kombu is naturally rich in free glutamate, the compound Kikunae Ikeda first isolated from it in 1908 to name umami in the first place. Dried shiitake mushrooms are rich in a different umami compound, a 5'-ribonucleotide called guanylate. Tasted apart, both are fairly mild. Combined, human sensory studies put the effect at roughly eight times stronger than glutamate alone, a real synergy rather than a simple sum. That's the identical chemistry that makes fish sauce taste so much deeper than salt water: fermentation leaves it rich in free glutamate, and the fish itself supplies inosinate, another 5'-ribonucleotide. Simmer soy sauce (or coconut aminos, for a soy-free version) with a strip of kombu and a handful of dried shiitake, strain it, and you're reproducing the same synergy by a different route.
Anchovies specifically, and the Worcestershire connection
Anchovies do triple duty in a Caesar dressing or a puttanesca: salt, umami, and a savory brine funk that reads as depth rather than fish once it's stirred into a sauce. White miso covers the salt and umami; a few chopped capers or a splash of their brine add the brine funk anchovies otherwise supply. Worcestershire sauce runs on the exact same logic in reverse: it's traditionally fermented with anchovies for its savory backbone, which is why our Worcestershire sauce page flags it as usually not vegan, but anchovy-free versions exist, and at least one long-running commercial brand simply swaps in soy sauce for the umami anchovies would have supplied. It's the same substitution this guide is making, already proven at commercial scale.
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A store-bought vegan fish sauce
The fastest fix when a recipe is built around the bottle itself, like a nuoc cham dipping sauce where fish sauce is the star rather than a background note. Formulated to hit both salt and umami at once, closer than most DIY blends manage for that specific job.
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Dried shiitake mushrooms and a strip of kombu
The pantry pair behind the umami synergy above, and genuinely reusable: the soaking liquid becomes a fast broth base, and the rehydrated mushrooms cook into the dish instead of getting thrown out.