Surströmming

Surströmming, sour herring, is Baltic herring preserved by fermentation. Preserving fish by allowing it to ferment is one of Sweden’s oldest techniques, and surströmming has been known since at least the 16th century, when it was already sold as reserve food. For a long time it was common food for peasants and fishermen in the north; in the 19th century it began to be appreciated by other groups and, over time, became a festive dish.

Local tradition says production began on the island of Ulvön, off Örnsköldsvik in the High Coast, in a summer of abundant catch when salt ran out and the fish ended up fermenting. In the 18th century, fermented herring gained importance as a long-lasting provision for the army. In the 19th century, canning helped distribute surströmming throughout Sweden. The island still has an operating salting house, and on the High Coast coast, in Skeppsmalen, there is a museum dedicated to the dish.

The herring is caught in spring, before spawning, left for a few days in strong brine and then placed in barrels with weaker brine, where it ferments for weeks. In summer it is canned, and fermentation continues inside the can, which sometimes bulges. Since 1940, the season begins on the third Thursday in August; the date was set because fish that had not yet fermented was being sold, and it was fixed by law until the end of the 20th century. It remains the traditional opening date.

The smell is intense, so the can is usually opened outdoors or inside a bucket of water. The most common way to eat it is the surströmmingsklämma: the cleaned fish on tunnbröd, the thin northern flatbread, with potato, chopped red onion, sour cream and sometimes tomato and dill, all rolled up. The meal, called surströmmingsskiva, brings friends and families together around tables in the yard at the end of summer.