Swedish Sour Fish: How to Serve Surströmming

Swedish sour fish, known as surströmming, is fermented Baltic herring with a famously pungent aroma and a salty, tangy flavor. It is usually served cold with warm potatoes, soft flatbread, onion, dill, and sour cream, so each bite can be built to taste.

This recipe is a practical serving platter rather than a guide to fermenting fish at home: use commercially prepared surströmming, which is a traditional Swedish specialty with regional and family variations. The mild potatoes and creamy accompaniments balance the fish, while flatbread makes it easy to serve as a shared meal.

Ingredients

1 can (about 10.5 oz / 300 g) commercially prepared surströmming; net weight varies by brand and the drained fish weighs less
1½ lb (680 g) small waxy potatoes, such as new potatoes
2 qt (1.9 L) water, for boiling the potatoes
1 tsp (6 g) fine salt, for the potato water
8 sheets or pieces (about 7 oz / 200 g) soft Swedish tunnbröd, or another soft flatbread
½ cup (75 g) finely diced red or yellow onion
½ cup (50 g) thinly sliced scallions
½ cup (120 g) sour cream
¼ cup (10 g) chopped fresh dill
2 tbsp (28 g) butter, softened, optional
1 lemon (about 4 oz / 115 g), cut into wedges, optional

Instructions

Set up for opening the fish. Keep the unopened can refrigerated and read its label before serving. Open it outdoors, away from doors, open windows, and guests who would rather avoid the strong smell. Set the can in a deep bowl or basin to catch brine, keep it pointed away from your face, and open it slowly. Fermentation can create pressure, so do not shake the can or try to open it close to anyone. A strong aroma is expected; a leaking can or one with a damaged seam should not be used.
Drain and portion the herring. Lift the fish out of the brine with a fork and let excess liquid drip back into the bowl. If you prefer a less salty taste, give the fish a brief rinse with cold water and pat it dry; rinsing also softens some of its sharp flavor. Remove any large bones you can see, then break or cut the fish into bite-size pieces. The fish is served cold and does not need to be cooked. Keep it covered in the refrigerator while you prepare the other ingredients.
Prepare the accompaniments. Dice the onion, slice the scallions, chop the dill, and spoon the sour cream into a small serving bowl. Cut the lemon into wedges if using it. Arrange the flatbread, butter, and toppings on a platter or in separate bowls. Keeping the toppings separate lets everyone choose how much onion, cream, and dill to use.
Boil the potatoes. Rinse the potatoes and place them in a saucepan large enough to hold them in a single, loosely packed layer. Add the measured water and salt. Bring to a boil, then reduce the heat to maintain a steady simmer. Cook small potatoes for about 18–20 minutes, until a knife slides easily into the center. Larger potatoes may need a few extra minutes. Drain carefully and let them steam-dry in the warm pan for 2 minutes; halve any that are too large for a flatbread serving.
Serve while the potatoes are warm. Put the cold herring on the platter beside the warm potatoes and accompaniments. To make a serving, place a potato or two on flatbread, add a small piece of herring, and finish with onion, scallion, dill, and a little sour cream. Add butter or a squeeze of lemon if desired. Start with a modest amount of fish; its flavor is concentrated, and diners can add more as they go.

Tips

Plan the opening location. Surströmming’s aroma lingers, so opening it outdoors is more comfortable than opening it in a kitchen. Set out the plates and toppings before you open the can, and keep the can and brine away from clothing and porous surfaces.
Let the potatoes do the balancing. Waxy potatoes hold their shape and have a gentle flavor that works well with the assertive fish. If you only have floury potatoes, boil them whole and handle them gently so they do not crumble when placed on the bread.
Adjust saltiness in small steps. The fish can vary in saltiness from can to can. Taste a small piece before deciding whether to rinse it, and keep the first rinse brief. Use unsalted butter and avoid salting the onion or sour cream; the herring usually supplies plenty of seasoning.
Choose a practical bread substitute. Tunnbröd can be difficult to find outside Sweden. Soft flour tortillas or thin, pliable flatbread are convenient substitutes, while crispbread gives a crunchier result and is more likely to break when folded.

Serving Suggestions

Serve the fish as a build-your-own platter, with the potatoes warm and the herring and toppings chilled. A useful serving order is flatbread, potato, fish, onion, dill, and sour cream, but there is no need to insist on one assembly method. Some diners prefer a small open-faced bite; others fold the bread around the filling. Keeping the fish and toppings in separate dishes also helps guests control the fish’s intensity and the amount of salt in each bite.

For a more substantial meal, add extra boiled potatoes, crispbread, or a simple green salad dressed lightly with vinegar and oil. A cold, nonalcoholic drink such as sparkling water or a tart berry drink is a refreshing option alongside the salty fish. If serving guests who are unfamiliar with surströmming, explain that the aroma is much stronger than the small portion of fish needed for each bite, and offer the potatoes, bread, and toppings as a meal in their own right.

Variations

Use a milder onion. Red onion gives the platter color and a sharp bite. For a gentler flavor, use finely sliced yellow onion or soak the diced onion in cold water for 10 minutes, then drain it well. This takes away some of its raw sharpness without adding sweetness or extra seasoning.

Change the creamy topping. Sour cream is easy to find and adds a cool, tangy contrast. Crème fraîche is a richer substitute, while plain full-fat yogurt is thinner and more tart. If using yogurt, serve it in a small bowl and expect a looser topping; avoid mixing it with the fish in advance.

Make individual bites. Cut soft flatbread into smaller pieces and top each piece with a potato slice, a small amount of fish, and the accompaniments. This is useful for a tasting-style meal because the amount of fish can be kept small. Have extra bread and potatoes ready so people can adjust the balance.

Use crispbread instead. A crisp Swedish-style rye bread offers a firm, crunchy base, though it is not as easy to fold as soft tunnbröd. Serve the toppings on the side and assemble each bite just before eating so the bread does not soften under the potato and sour cream.

Storage and Reheating

Keep the unopened can refrigerated and follow its storage instructions. Once opened, transfer any unused fish and a little of its brine to a clean, tightly covered container, refrigerate it promptly, and use it within 1–2 days or sooner if the product label directs. Do not leave opened fish or the assembled platter at room temperature for more than 2 hours; discard food that has been left out longer. Avoid storing the fish in an uncovered dish, since its aroma can spread to other foods.

Refrigerate leftover potatoes and toppings in separate covered containers within 2 hours. Cooked potatoes are generally best used within 3–4 days. Reheat only the potatoes, not the surströmming: warm them in a saucepan or microwave until leftovers reach 165°F (74°C), checking with a food thermometer. The fish is traditionally served cold, and reheating it would intensify its aroma. Assemble flatbread servings just before eating to keep the bread from becoming damp.

Frequently Asked Questions

What does surströmming taste like?

It tastes salty, savory, and distinctly tangy from fermentation, with a very strong aroma. The flavor is concentrated, so a small piece alongside potato, bread, onion, and sour cream is often a more approachable first bite than eating a large portion on its own. The intensity and saltiness vary between products.

Is Swedish sour fish the same as pickled herring?

No. Surströmming is fermented Baltic herring, while pickled herring is typically preserved in a vinegar-based brine or another seasoned liquid. They are different products with different aromas and flavors, so pickled herring is not an exact substitute. It can be served with the same potatoes and bread, but the result will be milder and more vinegary.

Can I open the can indoors?

It is best to open it outdoors because the smell is powerful and can linger indoors. Place the can in a basin to contain brine, open it slowly, and keep it pointed away from your face. Do not shake it. If you cannot open it outdoors, choose another dish rather than risking an unpleasant spill or lingering odor in a small room.

Can I make surströmming at home?

This recipe is for serving commercially prepared fish, not fermenting it. Fermenting fish requires controlled ingredients, conditions, and food-safety expertise; a home experiment is not a reliable substitute for a properly manufactured product. Buy a sealed commercial can from a reputable source, follow its label, and do not use a can that is leaking or has a damaged seam.

What can I use instead of tunnbröd?

Soft flour tortillas or another thin, pliable flatbread are the easiest substitutes. They make it possible to fold the potato and toppings around the fish, though they do not have tunnbröd’s particular flavor. Crispbread works if you want crunch; serve it open-faced and add the toppings just before eating to limit softening.

Can the fish be served without sour cream?

Yes. Sour cream is a cooling, tangy accompaniment, not a requirement. Leave it out or replace it with crème fraîche or plain yogurt. Add a little more potato, dill, or onion to the bread if you want a balanced bite without a creamy topping.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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