What is the Stinky Fish in a Can?

What is the Stinky Fish in a Can

The variety of food available on this planet is larger than the number of people living on it. Every country has its unique cuisine that depicts its culture. And every country also has that one food that makes non-natives think in disbelief, “how do they even eat that?”. After all, living in diversity is all about constant surprises and shocks. What is the Stinky Fish in a Can?

The stinky fish mentioned here refers to a Swedish dish called Surströmming. It is mainly eaten in northern Sweden and has been a part of their cuisine since the 16th century. It is a fermented, slightly salty Balistic herring fish. The word ‘Surströmming’ in Swedish literally means ‘sour herring.’ The fish has a foul smell due to the fermentation process done in tin cans, hence, the stinky fish in the can. Despite its smell, it is a famous cuisine loved by the Swedish. 

History Of Surströmming

  • The oldest fish fermentation evidence was found in the south of today’s Sweden.
  • Fermenting and drying fishes were common methods to preserve fishes and to increase their shelf life in older times.
  • Sweden’s soldier troops first consumed Surströmmings in the 17th and 18th centuries. As it was a food that was non-perishable, they were able to carry and eat it during long marches and wars.
  • Unlike today Balistic herrings were fermented only in weak brine solutions since salt was expensive back then.
  • They were sold in wooden barrels and were meant for immediate consumption.
  • The introduction of the canning technique helped increase the shelf life of the fermented fish at home and in shops.
  • It also made the exportation of fish out of Sweden possible.
  • It was called the food of the poor.

Surströmming Manufacturing Process

  • The harvest season for the Blaistic herring is between April and May when they are about to spawn.
  • They are put in a brine solution for 20 hours to remove the blood. After removing their heads, they are gutted and kept in a weaker brine solution inside to start the fermentation process.
  • The barrels are then stored under a controlled temperature of 15 to 20 degrees celsius.
  • Around July, the fishes are canned, and the fermentation continues inside the can until the can is opened.
  • The canned fish is distributed to wholesalers around the second half of August for public consumption.

Chemical Reaction Behind The Fermentation

  • The lactic enzyme in the fish’s spine starts decomposing the fish cells, i.e., autolysis occurs.
  • The bacteria form pungent-smelling acids like acetic acid, propionic acid. Hydrogen sulfide gas is also formed, which contributes to the foul rotten egg-like smell.
  • The salt further helps these bacteria responsible for rotting to thrive and grow the brine by raising the osmotic pressure.
  • The high osmotic pressure also prevents the decomposition of fish’s proteins into amino acids. It also helps the bacteria Halenaerobium, which decompose glycogen to organic acids, thrive in the brine.
  • These organic acids give a sour taste to the fish.

When to Eat Surströmmig?

The Swedish commonly eats the fermented herring on the “Surströmming Day,” which comes after the third Thursday of August. The festival is a fun gathering of people where they relish the taste and odor of Surstörmming together. But it is not restricted to these specific days; it is also eaten as daily food by the Swedish.

Where can you eat Surströmming?

The odor of this fermented fish is strong enough that your olfactory senses will remember it for a long time. The smell also tends to linger in the air and on the clothes for at least three days. So, it is suggested to eat Surstörmming outside in an open space.

  • They are readily available at every general store, mall, and restaurant in Sweden. The restaurants that serve it only do so at night when the crowd is less.
  • Outside of Sweden, it is available in online stores and some oriental grocery shops.

What do Surströmming smell and taste like?

According to a Japanese study, it is the most putrid smell in the world. People have compared its smell to that of dead, rotting bodies, cow manure. The common ground is that the smell is highly unpleasant and horrible to bear.  

The taste is a little better than the smell, mostly very acidic and salty. According to the common public’s opinion, just being able to eat a single bite of the fish without feeling nauseous is a big challenge in itself.

How to eat Surströmming?

To eat the fish straight out of the can is not very easy, even for the Swedish people, and so it is usually mixed with something.

  •  It is most commonly ate with a bread called tunnbröd, literal meaning “thin bread.” If the tunnbröd is soft, a fish roll is made out of it. With the hard bread, fish sandwiches are preferred.
  •  Onions, tomatoes, sour cream, and potatoes are used as the filling to go with the fish inside the bread. 
  • It is also eaten without the bread with just boiled potatoes, served with beer.

Is it safe to eat the fermented herring?

  • This fermented fish, despite the smell, is completely safe to eat as long as the can is not past its expiration date mentioned on it. 
  • Even if the can is not past the expiration date but has leaks, the fish is no longer fit for consumption.
  • One way to make sure the fish is still edible is to check for any bulge in the can. The excess release of gasses inside causes the bulge, indicating the fish is rotten and not edible.

How to open the Surströmming can safely?

Yes, there is a safe and an unsafe way when it comes to opening the can of this fermented fish. The can is filled with carbon dioxide produced by the bacteria Halenaerobium as it continues the fermentation process inside the can. Carbon dioxide, along with other gases present inside, makes the tin can explosive in nature. So it should always be opened away from fire.

The smell from the fish can linger around for days, becoming a bother for both you and your neighbor.  Even the airlines have banned opening Surströmming can while in flight or inside the airplane. Swedes suggest opening the can outside in open air, underwater to reduce the smell.  Holding your breath for a few seconds to avoid the initial blast of smell, which is the strongest, is also a way to do it.

Wearing gloves while opening the can is also advised by some. This is because the fishy fingers you get from it are almost impossible to get rid of for a few weeks.


Stinky fish in the can is the Swedish fermented fish. After a long time of fermentation in brine solutions, it develops its characteristic, infamous foul odor. It is a dish relished by Northern Swedish people. Surströmming is eaten after the third Thursday of August, marked as the “Suströmming Day,” or the Sour Herring Day. Although it has an unpleasant rotting dead body-like odor, it is safe to eat. It is a challenge for non-Swedish people to eat the fermented fish, but you can always get accustomed to the taste.

What is the Stinky Fish in a Can?

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