 2568/91 and subsequent amendments, the highest quality olive oil (Extra-Virgin olive oil) must feature a free acidity lower than 0.8%.Virgin olive oil is characterized by acidity between 0.8% and 2%, while lampante olive oil (a low quality oil that is not edible) features a free acidity higher than 2%.The increase of free acidity in olive oil is due to free fatty acids that are released from triglycerides.