Extra-virgin is the unrefined oil derived from the first pressing of the olives and has the most delicate flavor
Virgin is also derived from the first pressing of the olives but has a higher acidity level than extra virgin olive oil (as well as less phytonutrients and a less delicate taste)
Pure oil is a bit of a misnomer. Don’t be fooled if you see the term “pure” on the label, it means the oil is a blend of refined and virgin olive oils.
EVOO’s are best when used within four months of purchase, and most health benefits are lost in product that has reached 12 months of age