Surströmming is one of Sweden’s most famous, unusual, and passionately debated foods. Made from Baltic Sea herring that is lightly salted and allowed to ferment, it has a powerful aroma and a long cultural history. For visitors curious about Swedish food, surströmming offers an experience that goes far beyond its reputation as a challenging dish.
What is surströmming?
Surströmming is fermented herring from Sweden. The fish is usually caught in the Baltic Sea, lightly salted, and left to ferment in a controlled way before being packed into tins. Fermentation continues inside the can, which is why the containers may bulge and why the smell can be so intense when one is opened.
The name comes from two Swedish words: sur, meaning sour, and strömming, the regional Swedish name for herring caught in the Baltic Sea. Although the fish is often described simply as rotten herring, that description is misleading. Surströmming is fermented rather than putrefied, and the process is carefully managed with salt, time, and naturally occurring bacteria.
The finished fish has a soft texture and a strong aroma often compared with sour dairy, vinegar, onions, or sulfur. Its flavor is generally salty, savory, acidic, and deeply fishy. The smell is usually much more dramatic than the taste, especially when the fish is served with traditional accompaniments.
A short history of surströmming
Fermenting fish developed as a practical way to preserve food before modern refrigeration. In northern Sweden, fishing communities needed methods that could extend the life of a valuable catch through changing seasons. Salt was essential, but salt was also expensive. Using a smaller amount of salt and allowing fermentation made it possible to preserve herring with fewer resources.
Historical references to fermented herring in Sweden date back several centuries. The tradition became particularly associated with coastal areas of northern Sweden, including parts of Norrland. Families developed their own serving customs, and the dish became connected with late summer gatherings, local identity, and the end of the fishing season.
Today, surströmming is produced commercially by a small number of specialist makers. It remains a traditional food, but it is also a cultural symbol. Some Swedes eat it every year, while others have never tried it or strongly dislike it. That division is part of its modern identity.
How is surströmming made?
The process begins with small Baltic herring, sometimes called strömming in Swedish. The fish are cleaned and placed in a weak brine. They then ferment for a period of time before being transferred to tins, where fermentation continues.
Several factors affect the final result, including the size and condition of the fish, the amount of salt, temperature, and fermentation time. Producers must balance preservation with flavor. Too much salt stops fermentation, while too little can create food safety risks and an unpleasant result.
Unlike many preserved fish products, surströmming is not fully cooked, smoked, or dried. Its distinctive character comes from lactic acid fermentation. The fish remains soft, and the brine becomes part of the aroma and flavor. Once the can is opened, the contents are traditionally transferred onto flatbread rather than eaten directly from the tin.
Why does surströmming smell so strong?
The aroma comes from chemical compounds created during fermentation. These include sulfur compounds, acids, and other substances that can smell sharp, earthy, or egg-like. The smell becomes concentrated inside the sealed can, so opening it releases a sudden burst of odor.
This is why surströmming is often opened outdoors. The smell can linger in kitchens, cars, stairwells, and enclosed balconies. A calm day in a garden or a well-ventilated outdoor space is usually a better setting than a small apartment dining room.
Online videos often show people reacting dramatically to their first taste. Those reactions can be genuine, but they also turn surströmming into a kind of food challenge. In Sweden, the dish is not normally treated as a dare. It is traditionally served as part of a meal, with bread, potatoes, onions, and other ingredients that balance its intensity.
When is surströmming eaten?
The traditional season begins on the third Thursday in August, known as the surströmmingspremiär. This date marks the official release of that year’s surströmming in Swedish shops. It is not a legal requirement to wait until this day, but the custom has become an important part of the food calendar.
Surströmming parties are often held in late summer and early autumn. Friends and relatives gather outdoors, open the tins, prepare the accompaniments, and eat together. These events can be relaxed and social rather than formal. The food is usually served slowly, since the traditional bread rolls take time to assemble.
The tradition is especially strong in northern Sweden, although surströmming can be found in specialist shops and online retailers elsewhere in the country. Some local museums, restaurants, and cultural events also offer visitors a chance to learn about the dish.
How to serve surströmming
The classic way to eat surströmming is in a thin sandwich called a surströmmingsklämma. The fish is placed on Swedish flatbread, often called tunnbröd, together with potatoes, chopped onion, and sometimes sour cream or a similar creamy topping.
The bread and accompaniments soften the salty flavor and provide contrast to the fermented fish. There is no single universal recipe, so families and regions may use slightly different combinations. Some people prefer a soft flatbread, while others use crispbread or slices of boiled potato as a base.
Traditional accompaniments
- Thin Swedish flatbread or crispbread
- Boiled almond potatoes or other waxy potatoes
- Finely chopped raw onion, often red or yellow
- Sour cream or crème fraîche
- Fresh dill or chives
- Butter, when using crispbread
- Cold beer, aquavit, milk, or water
To prepare a simple serving, drain or rinse the fish according to personal preference, remove the backbone and larger bones, and break the herring into small pieces. Spread the bread with butter or sour cream, add potato and onion, then place a modest amount of fish on top. Beginners usually find it easier to start with a small portion rather than a large piece eaten alone.
How to open a can of surströmming
Opening the tin is part of the ritual, but it should be done carefully. The safest approach is to chill the can first and open it outdoors, preferably while holding it over a bowl or tray. Chilling can reduce pressure inside the container and help limit splashing.
- Keep the tin cold until you are ready to open it.
- Take it outside, away from doors, windows, and outdoor air intakes.
- Place the can in a bowl or open it under water if you are experienced with the method.
- Use a can opener slowly and protect your hands and clothing.
- Transfer the fish to a separate dish before serving.
- Seal leftovers securely and store them in the refrigerator.
Do not shake the can before opening it. A swollen can is not automatically unsafe because fermentation creates pressure, but a badly damaged, leaking, or unusually bulging container should be discarded. Always follow the producer’s storage instructions and check the use-by information.
What does surströmming taste like?
The taste depends on the producer, the age of the tin, and how the fish is served. The first impression is often salty and acidic, followed by a rich umami flavor. The texture is soft and moist, rather like other preserved fish products, although the fermented character makes surströmming distinctive.
People who enjoy it often compare the experience to a strong fish sauce combined with pickled herring. The smell can be overwhelming before the first bite, but bread, potatoes, onion, and dairy make the overall flavor more balanced. Surströmming is not usually eaten as a large main course. It is served in small portions as part of a shared meal.
It is worth separating personal taste from quality. A person may dislike surströmming because they do not enjoy fermented fish, but that does not mean the product has been prepared incorrectly. As with blue cheese, kimchi, or fermented vegetables, strong flavors can take time to appreciate.
Surströmming and Swedish food culture
Swedish food is often associated internationally with meatballs, cinnamon buns, open sandwiches, and fresh seafood. Surströmming shows another side of the country’s culinary history: practical preservation, regional ingredients, and foods shaped by climate and geography.
It also reflects the importance of seasonal traditions in Sweden. Many Swedish celebrations involve a particular dish, drink, or time of year. Surströmming parties connect people with coastal communities and older methods of managing food supplies. Even Swedes who do not eat it may recognize it as an important part of the national food conversation.
The dish is especially interesting because it has moved between everyday food, regional specialty, and cultural curiosity. It was once a practical preserved product, but today it is also served to visitors who want to understand northern Swedish traditions.
Common myths about surströmming
Is surströmming rotten?
No. The fish is fermented under controlled conditions. Fermentation changes the texture, smell, and flavor, but it is not the same process as uncontrolled decay. Even so, consumers should buy surströmming from reputable producers and follow storage instructions.
Do all Swedes eat it?
No. Surströmming is a regional specialty, and opinions vary widely. Some people look forward to the annual season, while others avoid it completely. Assuming that every Swedish person enjoys surströmming is similar to assuming that everyone in another country likes a particularly strong local food.
Is the smell worse than the taste?
For many first-time tasters, yes. The sealed tin concentrates the aroma, while the traditional accompaniments create a more balanced bite. Individual reactions differ, but the smell is usually the biggest challenge.
Tips for trying surströmming for the first time
If you want to try surströmming, approach it as a cultural food experience rather than a test of bravery. The setting makes a major difference. Eat it outdoors with someone who knows how to prepare it, and use traditional accompaniments instead of tasting a large piece straight from the tin.
- Choose a reputable Swedish producer.
- Try it during a proper surströmming gathering if possible.
- Open the can outdoors and keep a clean serving area nearby.
- Start with a small amount on bread and potato.
- Have water or another drink available.
- Expect a strong aroma, but judge the flavor separately.
- Respect the tradition and avoid treating the food only as a prank.
Visitors to Sweden can ask at specialist food shops, regional markets, or cultural centers about tastings. Northern coastal areas are the best places to learn about the tradition in its local context, although availability changes during the year.
Frequently asked questions about surströmming
Can you buy surströmming outside Sweden?
It is available in some Scandinavian food shops and through specialist online retailers, although shipping restrictions may apply. Because the tins can build pressure and need controlled storage, availability is more limited than for ordinary canned fish.
Should surströmming be eaten hot or cold?
It is normally served cold or at cool room temperature, usually with bread and other accompaniments. Chilling the unopened tin before serving is also recommended for easier handling.
Can pregnant people eat surströmming?
People who are pregnant, immunocompromised, or managing a health condition should ask a doctor or dietitian before eating fermented fish. Food safety guidance can vary by country, and fermented seafood may carry risks that are not relevant to healthy adults.
What drink goes with surströmming?
Cold beer and aquavit are traditional choices, while water and milk can also work well. The best option is one that refreshes the palate without competing with the fish, salt, and acidity.
Why surströmming is worth understanding
Surströmming may never become a favorite for everyone, and that is not the point of the tradition. It tells a story about Sweden’s coastline, preservation methods, seasonal celebrations, and regional identity. Understanding how it is made and served makes the experience more meaningful than simply reacting to its smell.
For anyone exploring fermented herring Sweden is known for, surströmming is an unmistakable place to begin. Served with flatbread, potatoes, onion, and good company, it becomes part of a shared Swedish food experience rather than merely a famous can with a powerful reputation.