As chef Malin Söderström opened the can, the trapped air escaped with a hiss and filled the balcony of her
waterside restaurant with the pungent odour of Sweden's infamous delicacy, surströmming.

Likened to the smell of rotten eggs, surströmming – fermented herring – has gained a following online where daring gastronomes film themselves trying the seafood, which should be opened outdoors because of the stench, and preferably underwater in a bucket.

From her seaside restaurant in the small fishing village of Skarsa more than 200 kilometres north of Stockholm based in a former herring processing factory, Söderström tries to defend the delicacy's reputation.

“The sourness with the saltiness together with the bread, potato and butter and onion, it's just fantastic,” the 51-year-old said outside the restaurant, dressed in her black chef's uniform.

Söderström's grandparents lived in one of the village's squat red-wood fishermen's houses near the water and she ate surströmming, directly translated “sour herring”, from childhood.

• What you need to know before trying Sweden's fermented herring

Chef Malin Söderström prepares a surströmming meal. Photo: Tom Little/AFP

Herring caught in the Baltic are salted after being caught and left to ferment for months in barrels before they are canned. Surströmming hails from northern Sweden, where it is most commonly eaten, but tins of the seafood are available from most large supermarkets across Sweden.

In recent years a museum has been dedicated to the divisive dish, and some restaurants dedicate a whole day to eating it to avoid offending other customers' noses.

But with customers down due to Covid-19, Söderström and her sister Anna called off their own surströmming day this year.

Instead they organised a small demonstration of how the dish should be enjoyed, inviting a handful of friends and colleagues to sample the culinary delight.

Opening the cans away from their tables, Söderström served it to the visitors on Swedish flat bread along with chopped red onions, boiled potatoes, dill, tomatoes, chives, sour cream and hard cheese.

• Five things about the Swedish summer that confuse newcomers

Cans of surströmming. Photo: Tom Little/AFP

Taking a break from the kitchen, 25-year-old chef Joseph Netzler tried the fish for the first time, sniffing it cautiously before tasting it with hard bread, dill and potatoes.

“It smelled a lot better than I thought it would, and the taste was good. It was kind of strong, kind of umami,” he said, sitting on the restaurant's balcony overlooking the village's small harbour.

“I think I've had my fill for a while,” he said, but added he might try it again in “one or two years”.

• WATCH: Dog tries fermented herring for the first time

Surströmming still inside the can. Photo: Tom Little/AFP

Söderström was bemused by YouTube videos of non-Swedes opening cans of surströmming indoors and trying to eat it whole with no accompaniments, often struggling to stomach the smell.

In one such video, a group of friends in the US opened the can at a table indoors, retching and choking before eventually trying the fish.

“The smell, you can't get over it, but the taste is just slimy,” one of the challengers said with a grimace after nibbling a piece of the herring with no accompaniments.

“Of course they think it's disgusting,” Söderström said with a smile. “I would think that as well if I had it the same way.”

“The whole meal is really important. Who you're eating with, where you're eating and how you're eating it. I want to keep that alive,” she said.

Article by AFP's Tom Little