What is Oil Winterizing?

Some vegetable oils, when stored in the refrigerator, do not stay completely liquid. The cooler temperatures may result in cloudiness from the crystallization of certain fatty acids that have a higher melting point than their neighboring fatty acids. This cloudiness may be eliminated by winterizing the oil - a commercial process that lowers the temperature of the oil, allowing the fatty acids with higher melting points to crystallize so that they may be filtered out. Commercial salad dressings and “salad oils” are usually made with winterized oil. Unwinterized vegetable oils that have crystallized in the refrigerator are perfectly edible and will revert to their clear character if allowed to come to room temperature.