The natural acid in olives is oleic acid. If the acidity of the cold-pressed oil is less than 0.8%, it is known as extra virgin olive oil. If the acidity is between 0.8% and 3.3%, the oil is called virgin olive oil. Any oil obtained from the first cold pressing that has a natural acidity above 3.3% cannot be sold as virgin olive oil. It is usually sent to a refinery to reduce the acidity and eliminate any other objectionable qualities in aroma and flavor, and is sold as “olive oil” or “pure olive oil”, a refined product.