Surströmming challenge: How Swedes actually eat the world’s worst-smelling food

When people think of Sweden, they tend to picture pop icons like ABBA, flat-pack furniture from IKEA or storybook characters like Pippi Longstocking. Swedish food, however, rarely inspires the same enthusiasm abroad, with one notorious exception: surströmming – fermented Baltic herring sealed in a pressurized can that is often branded as the world’s stinkiest food. The explosive potential of the can — combined with the contents’ putrid smell, some compare to raw sewage — has led airlines to ban passengers from bringing it aboard on flights.

In recent years, though, surströmming has drawn international attention online through the so-called “surströmming challenge.” The premise is simple yet brutal: Open the can — bulging with explosive gases from fermentation, much like champagne — and eat the aged fish without throwing up. Videos show people popping open tins that spew brine and fish bits everywhere, recoiling at the smell, often gagging dramatically and sometimes ending in a crescendo of screams and convulsive vomiting.

But those spectacles, according to devotees, miss the point entirely.

Joakim Hillberg, an aficionado and member of Sweden’s Surströmming Academy, says that, far from smelling like sewage, the odor is comparable to that of aged cheeses. To him, this very Swedish delicacy isn’t just an acquired taste, but an acquired smell.

“When you smell it, you try to kind of say, ‘Oh, it’s this type of cheese,’” he said, standing in his kitchen in Gothenburg. “Like, ‘Oh, this is like a very mature brie, or is it like a very mature Swiss, or like a red cheese.’ It’s not like all smell like brie, they smell different types. And then you say, ‘Oh, this one is really nice.’” The taste and texture can also be comparable to cheeses, he added.

The Surströmming Academy is applying to have this exemplar of Swedishness recognized as a UNESCO Intangible Cultural Heritage — alongside Switzerland’s yodelling, France’s baguette and China’s Kunqu operas.

The practice of fermenting fish in Sweden dates back thousands of years. The earliest evidence was uncovered in southern Sweden at a site estimated to be over 9,000 years old — predating evidence for winemaking by about a millennium.

The unique two-step brine fermentation technique that produces surströmming, however, is far more recent, with the earliest records dating to the 16th century. Produced in rural northern Sweden, it was long considered a “poor man’s food” that provided protein-rich herring from spoiling during unforgiving winters, according to Hillberg. Fermenting the fish in brine was likely a cost-saving measure, he noted, because salt was expensive.

For much of its history, surströmming was a one-step fermentation process: The fish fermented in the same brine-filled barrels in which they were stored and transported. Later, in the early 20th century, it became standard practice to can the herring and allow a second fermentation to continue inside the pressurized tin, Hillberg said.

“It’s kind of like sparkling wine,” he added: With champagne, one step of fermentation happens in the cask and the other in the bottle. “And here you have one in the cask and one in the can.”

This process creates the infamous convex bulge in the surströmming can, which Hillberg also compares to champagne.

“That’s from the gas fermentation there. It’s kind of like champagne or sparkling wine, you get pressure in the bottle. You don’t want to shoot the cork in someone’s eye. And you don’t want to shoot the brine in someone’s eye.” It’s a “very pronounced odor,” he said.

No longer a means of surviving rural winters, it has become a seasonal ritual. Many eat surströmming outside in late August, when the fermentation process traditionally ends, during what’s called a “surströmmingsskiva.” Family and friends gather outdoors to open the cans together, celebrating both the tradition and the end of summer.

With family roots in surströmming’s northern heartland, Hillberg sees the dish as a link to that heritage. Sour herring is something he can eat year-round and isn’t afraid to open indoors.

He demonstrated how to open a can without triggering an eruption: Angling it so the air pocket sits precisely at the top, he punctured the lid. Pried open, the can released a fizzing sound, like air escaping from a pinched balloon.

The odor that seeped out would be familiar to anyone who has walked along a mucky inlet at low tide. Perhaps there is a faint sewery note or two, but more so, it smells like coastal marshland — briny, organic, elemental. In a word, manageable — especially once framed as a sea rather than a sewer.

This year-old surströmming from Hillberg’s “stash” (which included at least one “vintage” from 2022) was soft in texture. After removing the bones and fins and cutting it into smaller pieces, the herring had the consistency of brie or camembert.

Compared to the smell, the flavor is relatively mild: salty, savory and deeply umami — somewhere between anchovies and a sharp cheddar, or aged brie. The aftertaste lingers longer, with a big hint of ammonia and notes of muck and mire dredged up from the sea floor. This may require some mental adjustment — and repeated exposure — to fully appreciate.

“It’s very briny, salty and they have these kind of fermented flavors,” said Hillberg with delight, as he took another bite of his open-faced surströmming sandwich.

It’s rarely eaten alone. Layered atop crisp flatbread with potatoes, butter, chives, tomatoes, lingonberries and sometimes cheese, surströmming becomes part of a larger composition. The surrounding ingredients temper the intensity, turning what might be overwhelming on its own into something balanced.

Hillberg suggests cleansing the palate with some good schnapps or aquavit and “Helan går,” a popular Swedish drinking song, to toast this very Swedish fish.

For those willing to look beyond the viral theatrics, surströmming reveals itself not as a stunt food but as a living piece of Swedish history — best approached outdoors, with good bread, generous toppings and an open mind.