Optimization of quality and yield of stockfish by end-drying in climatic controlled storage

Stockfish is gutted and de-headed unsalted fish, and airdried outdoor by hanging on racks. Cod (Gadus morhua) is the high-quality stockfish product and is dominant in volume. After outdoor drying from March, the stockfish is taken down from the racks in May/June, and normally end-dried in traditional warehouses with open gates to the surrounding air. New warehouses with controlled temperature and humidity has been built, and optimal storage air parameters have been established. Industrial test has been performed over two seasons at seven industrial producers, with comparison of quality and yield at different warehouses. By using controlled temperature at 2-4°C and relative humidity at 88-90%, it was shown that the stockfish quality was higher and the sales weight of this high cost product increased by 5-10%, compared with traditional methods. Another consequence was increase in quality and yield after rehydration, which is beneficial for the customers. Technical aspects of the heat pump system in controlled warehouses is discussed.