The World's Most Potent Fermented Fish

Surstromming is a Swedish herring fermented so intensely that it produces a powerful, unmistakable odor. Many consider its pungent aroma so overwhelming that it is often opened outdoors to avoid tainting a home.

This unique delicacy relies on lactic acid bacteria to ferment the fish, creating a flavor profile that is both savory and sharply acidic. The process is so active that cans often bulge due to the buildup of gases inside. Because of the intense smell, it is a common challenge for food enthusiasts around the world to try eating it without gagging. It has been a staple of Swedish tradition since the 1500s and remains a daring culinary rite of passage.