George I too will be very interested in Rox's response to your post and I'm sure will correct any of my misunderstanding. In the mean time, here's my 2 cents for what it's worth:
- There is a great difference in taste between olive oils but just as with wine everyone will have preferances and different types will be better with different foods.
- The differences in taste depend upon multiple factors, e.g., olive variety, where they're grown, when they're harvested, how they're processed, how it's stored, etc.
- Generally the EVOO (extra virgin olive oil) types are the first cold pressings that have the closest character to the fruit from which they come.
- To extract the most oil possible, other processing may be done by some producers which involves additional pressings, heat and/or maybe even solvent (?) extraction methods. Although they may still be "pure olive oil", more processing usually means lower quality & lower price.
- Many mass marketed oils are often blends from different countries of origin and various levels of quality. Some will be okay but seldom as good as those from a single producer or more limited region.
- First cold press EVOOs are great to use with many simple preparations that allow their character to come through, quick cooking dishes, as a final top dressing finish for serving, and of course with salads. Nothing quite like a nice garden ripened tomatos, really fresh mozzarella cheese, & fresh basil just dressed with a little salt, pepper and good quality balsamic vinegar & EVOO!
- Lesser quality pure olive oils can be used for things that may involve higher heat, longer cooking and/or higher levels of seasoning that would mask the subtleties of the oil itself.
- Have a tasting to appreciate the differences; I'd use small white plastic spoons and use plain bread as a palate cleanser between tastes. Pick up several bottles at various price points and from different regions - Italy, France, Spain, Greece, even California. For your first tasting you might want to limit yourself to a single country but several quality levels, then move on to comparing different countries and regions. Compare the color, clarity, aroma, initial taste impression, mouth feel and finish. Expect to see colors ranging from brighter greens all the way down to pale yellows or even almost colorless. Some will be more filtered (or centrifuged) for clarity while some may be more raw and cloudy. Some will have more olive fruit aroma while some will have almost none. Some will taste more like fresh olive fruit, some peppery, some more acidic than others while some will be almost tasteless; the raw unfiltered types usually have a grittier feel in the mouth. The better oils will leave a cleaner finish in the mouth while the lesser ones will just leave an oily aftertaste.
It's all a lot like wine. I think it would be best if we could go to France and Italy for the wine harvest then stay through the olive harvest and pressing - I'm thinking maybe late August through about December? We'd eat and drink quite well but might have to charter a jumbo jet to get us back home though!