Scandinavian Buried Fish: Gravlax

According to food ethnologist Astri Riddervold, Scandinavian fermented fishes— the original gravlax, Swedish surlax and sursild, Norwegian rakefisk and rakørret—were probably the result of a simple dilemma facing medieval fisherman at remote rivers, lakes, and coastlines, who landed many fish but had little salt and few barrels. The solution was to salt the cleaned fish lightly and bury them where they had been caught, in a hole in the ground, perhaps wrapped in birch bark: gravlax means “buried salmon.” The low summer temperature of the far northern earth, the airlessness, minimal salt, and added carbohydrates (from the bark, or from whey, malted barley, or flour), all conspired to encourage a lactic fermentation that acidified the fish surface. And enzymes from the fish muscle and the bacteria broke protein and fish oil down to produce a buttery texture and powerful, sharp, cheesy smell: the sur in sursild and surlax means “sour.”