Winterization of fish oil

A method of purifying a fish oil by winterization, the method comprising steps of:

• a) mixing a fish oil having a stearin content that is in the range of 2% (by weight) to 40% (by weight) with a solubilizing agent comprising an edible winterized fish oil to obtain a liquid mixture;
• b) incubating the liquid mixture at a first temperature that is in a range from +5° C. to +15° C.;
• c) filtering the mixture at a temperature that is equal to or lower than the first temperature to obtain a filtrate;
• d) incubating the filtrate obtained in step c) at a temperature that is lower than the temperature of steps b) and c);
• e) filtering the mixture from step d) at a temperature that is equal to or lower than the temperature in step d);
• f) optionally, performing additional incubating and filtering steps at increasingly lower temperatures, wherein each filtering step is performed at a temperature that is equal to or lower than the temperature of the previous incubation step;
• wherein the temperature of the last filtering step is in a range from −10° C. to +5° C., and wherein the solubilizing agent has a melting point that is lower than the temperature of the last filtering step;
• and g) isolating a liquid composition of the fish oil and the solubilizing agent that is suitable for human or animal consumption and that has a melting point lower than +5° C. in order to provide a composition of the fish oil after winterization that is a clear liquid without formation of stearin crystals following a cold test performed for a period of 1-3 hours at a temperature of 0° C.