Open air drying using sun and wind has been practiced since ancient times to preserve food.
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.
Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks on the foreshore.
Cod is the most common fish used in stockfish production, though other whitefish, such as pollock, haddock, ling and tusk, are also used.
In more recent times, freeze-drying, water binding humectants, and fully automated equipment with temperature and humidity control have been added.
Since the method was introduced by the Dutchman Jappe Ippes around 1690, the town had produced klippfisk and when the Spanish merchants arrived, it became a big industry.
The bacalhau or bacalao dish is sometimes said to originate from Kristiansund, where it was introduced by the Spanish and Portuguese fish buyers and became very popular.
This dish was also popular in Portugal and other Roman Catholic countries, because of the many days (Fridays, Lent, and other festivals) on which the Church forbade the eating of meat.