“Winterized” Olive Oils

Chemistry texts list the freezing point of pure oleic acid at around 3.9°C. Olive oil manufacturers don’t generally list a freezing temperature of olive oil because it is quite variable depending on the olive variety and ripeness of the olive at processing. Unlike the properties of a simple compound like water, olive oil is made up of hundreds of chemicals, many of which change with every extraction.

Like most fruit, olives have waxes on their epidermis (epicarp) to protect them from insects, desiccation, and the elements. These natural waxes are what allow an apple to be shined, for instance. If an oil is sent to a cold climate, or if it will be used in a product like salad dressing where it will be stored in the refrigerator, it is often “winterized” (chilled and filtered) to remove the waxes and stearates. A standard test to determine if olive oil has been sufficiently winterized is to put it in an ice water bath (0°C) for 5 hours, and no clouding or crystals should occur.