What Makes Olive Oil ‘Extra Virgin'?
Extra virgin olive oil is the highest grade of olive oil you can get. To be considered “extra virgin,” European law stipulates that it must be made in a certain way and have certain characteristics.
Extra virgin olive oil must be made exclusively from the first, cold press. It can be pressed only by mechanical methods of separation (no chemicals), such as a hydraulic press or a centrifuge.
Extra virgin olive oil cannot contain any chemical substances. It must be 100% pure olive "juice." This is, in part, what makes extra virgin olive oil one of the healthiest oils out there.
Before bottling, the oil is tested for acidity. In order to pass the test, it must have an acidity level lower than 0.8%, although many high-quality olive oils from Italy have an even lower acidity level (some as low as .1%)! For comparison, non-extra virgin olive oils can have acidity levels anywhere between 0.8 and 2%. Acidity greatly affects the flavor of the end product, so this is a crucial aspect of the testing phase.
There are three main enemies of extra virgin olive oil: light, heat, and oxygen. Any of these factors could affect the olive oil during production (and post-production), causing it to have some kind of sensorial defects. For this reason, the olive oil is tested first to make sure nothing is off before it's bottled and labeled "extra virgin."