Thus, it is better to choose a refined oil for frying (where flavor of the oil is lost anyway) and, if possible, an unrefined oil for salads. Unrefined oil should never be used for frying, but it is still safe to use for simmering. However, unrefined oil is also more sensitive to storage conditions and thus it is better bought in small quantities and stored in cool, dry places. If stored improperly or for too long, unrefined oil is more likely to alter and become unusable.

The extra virgin oil is the oil obtained from the first cold press of the main ingredient. The virgin oil is obtained at the second press. Finally, the plain oil (the one which is labeled simply "olive oil" or "sesame oil") can be obtained in a variety of ways, including industrial process. Keeping in mind that the closer to nature, the healthier.

The best cooking oil would be the extra virgin followed by virgin oil. The main difference between the extra virgin and virgin types of oil is mainly of acidity level, thus of taste. The extra virgin oil also tends to have more anti-oxidants and is thus considered better for preventing cancer and heart diseases.