Extra virgin olive oils are produced from the first pressing, which is performed within 24 to 72 hours of harvesting. Mechanical or hand pressing are the only methods used to obtain extra virgin olive oil. No heat or chemical processes are used. The oil obtained from the first pressing is the only olive oil that can be classified as extra virgin (or virgin, depending on the natural acidity level).
Premium Extra Virgin
"Premium Extra Virgin" refers to the best olive oil possible in terms of acidity, quality, aroma, and flavor. Some brands may have natural acidity rates as low as 0.225%. Because it is the most expensive, it is best to use premium extra virgin for dishes in which the olive oil will not be heated. Heating olive oil causes it to lose some of its flavor, so it isn't necessary to use the most expensive grades for cooking. Use premium extra virgin olive oil in salads or as a condiment when flavor is of most importance.
To be classified as extra virgin, the acidity level of the olive oil can be no greater than 1%. Like premium extra virgin, it is best to use extra virgin for dishes in which the olive oil will not be heated, such as in salads or as a condiment.