Imagine opening a can of fish and literally having to cover your nose so that its aroma doesn't make you vomit. Surstromming, a traditional Swedish product, often tops lists of the most unpleasant or disgusting foods on the planet, and for good reason. The extremely strong smell is due to its unusual preservation process and a method of consumption that many find difficult to imagine. Even so, it remains a vital part of Swedish culinary culture and is consumed every year during specific celebrations. Its name itself hints at what it offers: "'Surstromming' literally means fermented herring." From there, everything revolves around fermentation, time, and an aroma that has generated equal parts fascination and repulsion.

What is surstromming and what does it smell like?

According to the Lovferments website, small herring caught between April and May, when they reach the ideal point for this process, are used in its production.

After being caught, the fish are placed in a strong brine for approximately 20 hours to completely remove the blood. They are then transferred to a milder brine with a lower salt concentration, which allows fermentation to continue in a controlled manner. This step is key, as the low salt content doesn't stop bacterial activity but rather encourages it.

Next, the herring are stored in barrels kept in rooms with a stable temperature, between 15 and 20 degrees Celsius.

Finally, they are packed in tin cans, where fermentation continues until consumption. This long fermentation is precisely what creates the smell, which some describe as pungent, very intense, spicy, acidic, and even smelling like rotten fish or garbage left out in the sun. Hence the reason it is considered the most disgusting food in the world. The Spanish streamer Ibai Llanos, who tried to eat surstromming six years ago,He recently posted a video where he finally dared to try it and gave his own description of the aroma. He even showed how flies started swarming after opening the can. "It smells like a mixture of vomit, rotten fish, sewage, and very strong cheese. How can food smell like sewage?" the famous YouTuber wondered. He also explained that a can of surstromming shouldn't be opened in a closed room, but only in open spaces and underwater, due to the fermentation gases. In fact, some cans tend to bulge. After adding the herring to a slice of toast with butter, Ibai Llanos commented: "It might be the most disgusting thing in the world, but it looks amazing. I'm a big fish fan." He also pulled out a huge bone and, right after taking a bite, emphasized: “It’s incredibly salty. It’s like an overly salted fish. I just don’t get the point of eating this, with eight kilos of salt on it.”

In April 2006, several airlines, including Air France and British Airways, banned surstromming from being carried on board, considering the cans potentially explosive. Following this decision, it stopped being sold at Stockholm International Airport, although local producers have maintained that the risk is minimal. Would you dare to try it?