Stockfish is Norway´s longest sustained export commodity, and the socioeconomically most profitable export over the centuries. Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks on the foreshore, called "hjell". The drying of food is the world´s oldest known preservation method, and dried fish has a storage life of several years. The method is cheap and effective in suitable climates; the work can be done by the fisherman and family, and the resulting product is easily transported to market.
Cod is the most common fish used in stockfish production, while other whitefish, such as pollock, haddock, ling and cusk, are used to a lesser degree.
Stockfish is first mentioned as a commodity in the Icelandic saga "Egilssaga", when the Chief Torolv Kveldulvssøn in year 875 AD, shipped stockfish from Helgeland in mid Norway to Britain. This product represented most of Norway´s national income from Viking age throughout medieval age.
Stockfish is extremely popular and is widely consumed in Catholic Mediterranean countries, notably Italy. (Stockfish is called stoccafisso in most Italian dialects, but confusingly baccalà which normally refers to salt cod in the Veneto). Historically, Kristiansund is the dried cod capital of Norway, and you cannot leave town without tasting "Bacalao" at one of the town´s fish restaurants. The science of producing good stockfish is in many ways comparable to that of making a good cognac, Parma ham, or a well matured cheese.
The Slow Food movement insists that all these artisanal products must be made on a small scale and given time to mature. The fish is prepared immediately after capture. After gutting the fish, it is either dried whole, or split along the spine leaving the tail connected. The fish is hung on the hjell from February to May. Stable cool weather protects the fish from insects and prevents an uncontrolled bacterial growth.
A temperature just above zero degrees Celsius, with little rain, is ideal. Too much frost will spoil the fish, as ice destroys the fibers in the fish. The climate in northern Norway is excellent for stockfish production. Due to the stable conditions, the stockfish produced in Lofoten is regarded as the best. The traditional cod harvest in Lofoten also takes place during the best drying time. Due to a milder and more humid climate, salted/dried whitefish (klippfisk) was more common in the fisheries districts of Western Norway.
After its three months hanging on the hjell, the fish is then matured for another two to three months indoors in a dry and airy environment. During the drying, about 80% of the water in the fish evaporates. The stockfish retains all the nutrients from the fresh fish, only concentrated: it is therefore rich in proteins, vitamins, iron, and calcium. After sorting by quality, most of the stockfish is exported to Italy, Croatia and Nigeria. In Norway and Iceland, the stockfish is mostly used as a snack and for lutefisk production. In Italy, the fish is soaked and used in various courses, and is viewed as a delicacy.