Before refrigeration, people used various methods to preserve foods. Salting food was a popular choice, both because salt is an abundant material and because of the simplicity of preserving food with it. People along coastal areas in particular used salting -- also known as curing -- to preserve fish. Salt curing removes the water from fish, postponing the onset of rotting. Salted fish may be left unrefrigerated for several weeks, but will last longer if kept cool after curing.
Gut and clean the fish. First, cut off its head and slice through the bottom of the fish from head to tail to allow it to bleed. Then cut the fish open, remove its innards and debone it. Cut the meat into the desired portions, leaving the skin on.
Sprinkle a layer of salt over the bottom of a nonreactive container.
Lay fish pieces in a single layer, skin side down. Do not overlap the fish.
Cover the fish with a salt layer. Repeat the salt and fish layers until the container is full, ensuring that the top layer is salt.
Weigh down the fish by placing dishes or a small board over the top salt layer and placing weights on top of platform. For small salting jobs, use dishes and clean, full soup cans. For larger salting operations, use planks and paint cans or free weights.
Wait until the salt has sucked the moisture from the fish. This takes anywhere from 10 to 20-plus days. The process takes longer in cold weather and with thicker pieces of fish, while warm weather and small fish will accelerate the salt curing.
Wash the fish pieces thoroughly. Arrange them in a single layer and put a board or plate over top. Weigh down the surface with weights or soup cans. Leave the fish for several hours. This step dries the fish from following the washing.
Lay the fish outdoors over a grate or on a wooden frame for ventilation in a sunny location. Allow the fish to dry for several days in a moisture-free environment to completely dry.
Plan on a salt to fish ratio of 1 to 5 -- that is, 1 pound of salt for every 2.27 Kilogram of fish.
Do not leave the fish in the salt mixture too long or take it out too soon. Overcuring makes fish too salty and inedible, while undercuring can leave raw spots.