At the Market: Selecting Olive Oils
Choosing an olive oil at the grocery store can be a daunting task, but if you follow some basic principles you will find the freshiest and the best offered.
How to Shop for products in the Supermarket: Extra Virgin Olive Oil
These days, supermarket shelves are filled with so many different kinds of extra virgin olive oils. Without the benefit of tasting them, it may seem impossible to judge their quality. However, learning to read their labels properly can give you a bit of insight into the background of each oil
Good extra virgin olive oil should be grown, pressed and bottled in a single country. "Product of Italy" does not necessarily indicate that the olives are grown or pressed in Italy, only that it was packaged there.
This indicates that no heat was used to extract the oil from the olives. Adding heat to the olives allows producers to extract more oil from the olives, but simultaneously destroys the delicate flavors and aromas so prized in a good extra virgin olive oil. It should be noted that "cold pressed" means at a temperature not to exceed 80.6°F, not actually "cold."
A good bottle of extra virgin olive oil with have a "pressing" date or sell-by date (usually one year after it is pressed) on the label, so you will know the age of the product. Unlike wine, olive oil does not age well. If you store it properly, away from light and heat (never on the back of the stove!), a good bottle of olive oil will not go rancid during its time in your kitchen. A good rule of thumb is to buy what you consume in a month to maintain fresh olive oil.
Despite our natural inclination to associate a rich, deep color with better flavor and quality, the actual color of olive oil is not an accurate judge of its quality. In fact, extra virgin olive oils can range in color from deep grassy green to bright, yellowy gold. This variance is due only to the level of chlorophyll in the olives when they are pressed.
"Pure" and "Light" Olive Oils
These olive oils are heat-treated, resulting in a neutral-flavored oil that is a popular choice for baking and also deep-frying, due to its higher smoking point. It is important to note that these oils still have the same healthy benefits (as far as being a "good fat" for lowering cholesterol) as extra virgin oil, although not the antioxidant benefits.
All this said, if you can shop for olive oil in a market that allows you to sample them before you buy, that is the best place to start. The different flavor profiles that a top-quality extra virgin olive oil can have (spicy, floral, nutty, fruity, buttery, herbal) can only be judged on the nose and the tongue, not with they eye. A good olive oil will always taste "clean" and "fresh" on your palate, and never leave a waxy residue when swallowed. The flavors can be subtle or even assertive, but never overpowering in a way that indicates rancidity. The Italian word amato is used to describe the desired effect of swallowing a top-quality extra virgin olive oil: a peppery finish that begins on your tongue then migrates to back of your mouth.