Dependence of the Viscosity of Olive Oil on Temperature and Storage Life

Abstract

Olive oil becomes more and more popular in all European countries. When the temperature decreases, oil begins to crystallize and solidify. This process generally starts between 8°C and 12°C; the most favorable storage temperature with regard to oil quality seems to lie between 8°C and 12°C. These temperatures do not have to be kept exactly in the range preset above, but have shown their value in long-term storage. Nevertheless, oil may begin to turn from liquid to solid at much higher storage temperatures, particularly if storage conditions are unsatisfactory. It should be remembered that several days are necessary for its crystallization and solidification. Once this crystallizing stage is reached, it is too late to send the oil to a new customer. As a rule, then, most of the oil that crystallizes and solidifies when the temperature drops results from faulty long-term storage conditions, as it is very difficult to change the crystallized oil back into the liquid state. The increase in viscosity with cooling and time represents the reversal of all the transformations that take place during refining and is responsible for cloudiness and sediment formation in properly refined oils. The regression range of extra virgin, factor, or superior edible oils is precisely determined by the producers. If the oil is not used within a certain time after this period, even oil with the best storage conditions will begin to turn from liquid to solid. [1][2]