George and Fellow ChD's, Don't expect me to go isotopicking down the the biosynthetic technique pathways for the authentication of extra-virgin olive oil. I lead a simpler life. Mediterranean Diet (p. 459 paraphrased) The International Olive Oil Council sets the standards (which are many) for multiple grades of olive oil. Two of these concern us as consumers: unrefined Extra Virgin olive oil must be extracted from the best olives by physical or mechanical means without adding chemicals. It's either crush and press or centrifugal extraction. But Pure olive oil which is made from lesser olives (also without chemicals) is refined to make it odorless, colorless, and tasteless. Some extra virgin or virgin (not usually available commercially) oil is then blended with the "pure" olive oil to give it some character. Second pressings and chemical processes come after these, though Virgin (when we can get it) might suit some of us better than "Pure," more acidic but more olive flavor. Pure is generally the choice for cooking and has a higher smoking point than EV with its vegetable particles unrefined. Extra Virgin is the choice for using fresh, on salads, on bruschetta or crostini, for example, and to many people is a sauce in itself. Olive oil itself is raw. It is also as complex as fine wines. But, unlike fine wines olive oil, most decidedly, does not improve with age. The fresher; the better. French, Italian, Lebanese, and Spanish olive oils (among others) vie for international favor in color, flavor, and aroma among professional tasters by cultivating certain of these "organoleptic characteristics." No matter where it comes from, extra virgin olive is supposed to have a free acid content of less than 1 percent and "perfect" color, aroma, flavor. I am mindful of the warnings on this list about infusions, but I make them with extra virgin only and in the "standardized olive oil pouring container." They get used up too fast to spoil. Heart health note: Best of all, however, in the Seven Countries Study of men on the island of Crete, they were getting 40% of their daily calories from fat, but the fat was predominantly olive oil. Their mortality rates from coronary artery disease and stroke were among the lowest in the world. Gareth the ChileKnight