There are many types and qualities of olive oil available, but in order to be considered pure olive oil, the oil must be extracted directly from the olive. The oil may not be obtained through solvents or by mixing with any other type of vegetable oil. However, even among the pure olive oil there are several types or grades. The three basic grades of olive oil are: extra virgin, virgin and semi-fine virgin.
Extra virgin is used to describe the olive oil that is the highest quality and most flavorful. Extra virgin olive oil must be free of acidity, produced entirely by mechanical means and at a temperature low enough that no degradation of the oil occurs (less than 86°F, 30°C)
In order to receive the status of “extra virgin” the olive oil must pass an official chemical test as well as a sensory evaluation by a trained testing panel that is recognized by the International Olive Council. The taste of extra virgin olive oil is described as “fruity” and is best appreciated in its uncooked state.
Virgin olive oil is classified as a “good” oil. Like extra virgin olive oil, it does not contain any refined oil, but it can have an acidity level of up to 2%. Because of its lesser quality in taste, virgin olive oil is best used in cooking.
Semi-fine Virgin Olive Oil
Semi-fine virgin olive oil can have an acidity up to 3.3%. An inferior oil, the flavor of semi-fine virgin olive oil is not strong enough to be tasted in its uncooked state and should only be used in cooking.
If olive oil is refined beyond the first pressing then it loses the grade of “virgin.” These low quality oils are processed with heat, chemicals or filtration until they become clear, odorless and flavorless. Due to their extremely long shelf life these refined olive oils are usually combined with virgin oils and used in foods that are “packed in olive oil.”