The Importance of Low Acidity In Olive Oil We often hear about the importance of low acidity, that is below 0.8%, in extra virgin olive oil. What is low acidity and why it is so important are important questions. It is important because the lower the percentage of oleic acid, the higher the quality of the olive oil. The term oleic means related to, or derived from, oil or olive. Oleic acid is a naturally-occurring mono-unsaturated omega-9 fatty acid found in various animal and vegetable sources. The degree of acidity referred to in extra virgin olive oil refers to the proportion of free fatty acids, not to the taste. To be truly great extra virgin olive oil it must be virtually free of acidity. The higher the content of acidity the more unpleasant is the flavor of the oil. Different factors are responsible for the level of acidity in the production of olive oil, but quality of the soil is of utmost importance. Good harvesting and pressing practices are also important. Olives should not be harvested from the trees and not picked off the ground. Pressing equipment should be kept clean and olives should be processed shortly after picking in order assure low acidity and better overall quality. Incidentally, purchasing your olive oil from a trusted merchant is also crucial!