Mention the word surströmming to most Swedes and they’ll turn up their noses in disgust. It’s best translated as “fermented Baltic herring” – though to the non-connoisseur, the description “rotten” would seem more appropriate. The tradition of eating the foul-smelling stuff began on Ulvön sometime during the sixteenth century when salt was very expensive; as a result just a little was used in preserving the fish, a decision which inadvertently allowed it to ferment.
The number of salthouses producing the herring has dwindled from several hundred early in the twentieth century to around twenty to thirty now. Today, surströmming is made in flat tins containing a weak salt solution. Over the course of the four- to ten-week fermentation process, the tins blow up into the shape of a soccer ball under the pressure of the gases produced inside. Restaurants refuse to open the tins on the premises because of the lingering stink that’s exuded, not unlike an open sewer; the unpleasant job has to be done outside in the fresh air.
The season for eating surströmming begins on the third Thursday in August, ending around two to three weeks later, when supplies run out. The fish can be accompanied with the yellow, almond-shaped variety of northern Swedish potatoes and washed down with beer or akvavit; alternatively it’s put into a sandwich, perhaps with onion or tomato, all rolled up in a piece of tunnbröd, the thin unleavened bread traditional in this part of the country. More information at w surstromming.se.