Surströmming tastes intensely salty with a deep, savory umami richness, a sour acidic tang, and a faint cheesy quality that people compare to aged gruyère or brie. The flavor is complex and layered, but it’s the smell that hits you first and hardest. Most people who gag at surströmming are reacting to the aroma, not the taste itself, and the two experiences are surprisingly different.
The Flavor, Layer by Layer
The dominant note is salt. Surströmming is brined herring that ferments for at least six months inside the can, and that process concentrates a sharp saltiness that hits immediately. Right behind it comes a powerful umami, the same deep savory quality you find in fish sauce, soy sauce, or aged parmesan. Swedish suppliers compare it directly to Vietnamese fish sauce and ancient Roman garum, which makes sense: all of these are products of fish protein breaking down over time into intensely savory compounds.
Then come the secondary flavors. Lactic acid bacteria developed during fermentation give the fish a faintly cheesy note, similar to a ripe brie or gruyère. There’s also a subtle pepperiness, often compared to pungent arugula, that adds a slight bite. And because the fermentation produces acetic acid (the same acid in vinegar) and other organic acids, there’s a distinct sourness. The Swedish name literally means “sour herring.”
The texture is soft and somewhat mushy. The enzymes naturally present in the fish flesh spend months breaking down proteins during fermentation, so the meat lacks the firmness of fresh or even canned fish. It’s closer to a very soft pâté than a fillet.
Why the Smell Is So Much Worse Than the Taste
Opening a can of surströmming is genuinely one of the most intense smell experiences in food. Gas chromatography analysis of the volatile compounds inside the can reveals massive amounts of trimethylamine (the chemical responsible for “fishy” smell) and sulfur compounds. The fermentation bacteria also produce hydrogen sulfide (rotten eggs), butyric acid (rancid butter), propionic acid (sharp pungency), and acetic acid (vinegar). Carbon dioxide builds up too, which is why the cans bulge on the shelf and pressurize over time.
All of these gases release at once when you pop the lid. The smell is so overpowering that it can trigger a gag reflex in people standing several meters away. This is why Swedes traditionally open the can outdoors, often submerged in a bucket of water to trap the initial burst of gas and prevent the brine from spraying.
Once the can is open and the fish is rinsed, the smell diminishes considerably. It doesn’t disappear, but it calms down enough that the actual flavors become accessible. People who push past the opening experience often find the taste far more manageable than expected.
How Swedes Actually Eat It
Almost nobody in Sweden eats surströmming straight from the can. The traditional preparation is a surströmmingsklämma: a wrap made with tunnbröd (a thin, soft Swedish flatbread), sliced almond potatoes or waxy fingerlings, finely diced red onion, a generous dollop of gräddfil (Swedish sour cream), and fresh dill. Each ingredient plays a specific role in taming and balancing the fish.
The potatoes add starchy mildness. The sour cream rounds out the saltiness with fat and a gentle tang. The raw red onion provides crunch and sharpness that cuts through the richness. And the flatbread holds it all together into something that, when assembled properly, tastes more like an intensely flavored Scandinavian open sandwich than the prank food the internet makes it out to be. A cold glass of milk is the traditional drink pairing, chosen specifically because its mild fat content softens the salt and fermented funk.
If you buy a can that contains whole fish rather than fillets, you’ll need to gut the fish yourself before eating, removing the backbone and sometimes the skin.
What Creates the Flavor
The taste of surströmming is a direct product of its unusual fermentation. Herring are caught in May and June, just before spawning season, when they’re lean and haven’t fattened up. The fish are placed in a strong brine for about 20 hours to draw out blood, then beheaded, gutted (or sometimes left ungutted), and packed into cans with a weaker brine solution.
The key detail: the brine uses just enough salt to prevent the fish from rotting, but not enough to stop fermentation entirely. This creates conditions where specialized salt-loving bacteria, primarily a genus called Halanaerobium, thrive. These microorganisms break down the fish’s glycogen (stored sugar) into organic acids, which is what makes the herring sour. Meanwhile, the fish’s own natural enzymes slowly break down proteins in the flesh, producing the deep umami and soft texture. The composition of bacteria varies noticeably between brands, which is why two cans of surströmming from different producers can taste quite different from each other.
What First-Timers Should Expect
If you’re trying surströmming for the first time, your biggest challenge will be getting past the smell long enough to actually taste the fish. Open the can outside. Consider opening it in a basin of water. Have your accompaniments ready before you crack the lid, because the longer the fish sits exposed to air, the more the smell permeates everything nearby.
Start with a small piece of fillet wrapped in flatbread with plenty of potato, onion, and sour cream. Eaten this way, the sharpness and fermented funk blend with the cooling, creamy elements into something genuinely balanced. Many first-timers are surprised to find the taste interesting rather than revolting, even if the smell nearly defeated them moments earlier. The flavor has more in common with a strong cheese or a potent fish sauce than with something spoiled.
That said, this is one of the most polarizing foods on the planet for a reason. Even experienced eaters describe it as an acquired taste, and not everyone acquires it. The combination of extreme saltiness, funk, and soft texture is simply not for every palate, and there’s no shame in stopping after one bite.