satanboy
Psychonaut seven

Anyone here ever tried this?
fermented Baltic herring and is a staple of traditional northern Swedish cuisine. The Baltic herring, known as strömming in Swedish, is smaller than the Atlantic herring, found in the North Sea, and traditionally the definition of strömming (Baltic herring) is herring fished in the brackish waters of the Baltic north of the Kalmar Strait[1] The herring used for surströmming are caught just prior to spawning. The fermentation starts from a lactic acid enzyme in the spine of the fish, and so the fermentation is by autolysis; together with bacteria, pungent smelling acids are formed in the fish such as propionic acid, butyric acid and acetic acid. Hydrogen sulphide is also produced.
The salt raises the osmotic pressure of the brine above the zone where bacteria responsible for rotting (decomposition of proteins) can thrive and prevents decomposition of fish proteins into oligopeptides and amino acids. Instead the osmotic conditions enable the Haloanaerobium bacteria to prosper and decompose the fish glycogen into organic acids, making it sour (acidic). Fermented fish is an old staple in European cuisines; for example the ancient Greeks and Romans made a famous sauce from fermented fish called garum[2] and Worcestershire Sauce also has a fermented fish ingredient.