It starts simply: You hold a bottle of olive oil up to the light, checking the color. Next thing you know, you are inhaling the aroma of a new variety, tasting it, rolling the oil over your tongue. Suddenly, you want to learn more, to find the best olive oil you’ve ever tasted. Here’s a primer for those of you who have already discovered delight in olive oil. And for those of you who haven’t, here’s your chance to learn what makes it so wonderful.

Types of olive oil

First, you might be wondering about how something might be “extra virgin”. Well, this aspect of olive oil relates to its quality. Because the olive is a fruit, the quality judges say the less that olive oil is handled, the better the product (that is, less handled equals more “virgin”. Olive oil is ranked by international organizations, like the International Olive Oil Council, according to how it is produced as well as its acidity. The primary types are:

• Extra-virgin olive oil. This rating is the highest and verifies that the oil was extracted only from the first pressing of the olives and without the use of chemicals or heat. The olives used for extra-virgin olive oil are generally green. The oil has no off-flavors and the acidity is less than 1%.
• Virgin olive oil. This oil is pressed from riper or lower-quality olives but is otherwise made in the same manner as extra virgin. The taste and aroma are judged to be less than extra-virgin oil. Its acidity is 1.5%.
• Refined olive oil. This is a poor-quality olive oil in which chemicals are used to extract the last bit of oil from the mash. Its taste is bland and its acidity 3.3%.
• Olive oil. Often called pure olive oil as a marketing ploy, this oil is commonly made by adding a little virgin oil to refined olive oil. It is lighter in color and has little taste.
• Light or extra-light olive oil. This oil actually has the same amount of calories as the other categories and is created by chemical extraction from the poorest quality of olives. “light” or “extra-light” is just a marketing spin.

Health values

Olive oil is a monosaturated fatty acid rich in antioxidants. It does not have the same cholesterol-raising effects of saturated fats.

Also, olive oil is central to the Mediterranean diet. Some specialists say the diet is particularly healthy because people who live in the Mediterranean region generally eat more grains, nuts, legumes, vegetables, fish, and olive oil than people in other regions (particularly North America). Lower cardiovascular disease around the Mediterranean is associated with this type of diet.

How to judge olive oil

As with wine, identifying a top-quality olive oil means checking different oils for taste and aroma. There are hundreds of different brands of extra-virgin olive oil. And like wine, the taste is greatly affected by the climate and the soil in which the tree grows. Some experts say that olives grown in higher elevations have more intense flavors than those grown in lowlands. Trees raised on rocky slopes produce flavors different from those in deep loam.

If you really want to judge olive oil, then you should taste several varieties. Since olive oil is sometimes expensive, buy the smallest bottles available. Better yet, throw a tasting party and get your friends to pitch-in, with each of them bringing a different bottle.

When tasting, do what the experts do in the great olive-producing countries of Italy, Spain, Portugal, and Greece. First, open the bottle of extra-virgin olive oil and smell it. You should get a clear and pleasant sense of the olive fruitiness. Now pour about a teaspoon into a small glass and warm it in your hands. Turn the glass so the oil coats the sides as you warm it, then inhale a bit, pulling the oil back on your tongue as if tasting a fine wine for the first time.

Some varieties of newly pressed extra-virgin oil will have a bite to it, a peppery sense that you can feel in your throat. This can be great when dipping some warm and crusty bread into a plate of premium oil. Others will have less. You can search out what suits your tastebuds best.

If you are tasting more than one variety at a time, spit out the oil and rinse your mouth well with water before trying the next one.

Caring for olive oil

Unlike basic cooking oils, premium olive oil requires some tender loving care. Its primary enemies are air, heat, light, and age. Any of these alone or in combination causes the oil to break down and turn rancid.

Keep the oil in an airtight container, don’ leave it sitting out where sunlight will heat it, and use it or lose it. As it ages over several months and is exposed to air, oxidation causes the oil to break down and eventually become rancid.

A bottle being used daily should be stored where the temperature ranges between 50° and 60°F. For long-term storage, olive oil keeps very well in the refrigerator. Instead of keeping just one large bottle in the refrigerator, keep one small glass bottle in the cupboard for daily use and the rest in smaller airtight glass bottles in the refrigerator. This way, it’l pour easily out of the bottle. (Cold oil oftentimes congeals and turned cloudy. Once it warms, it turns clear again; refrigeration does not affect negatively affect it.)

Where to use olive oil

Extra-virgin olive oil is ideal for salads and vinaigrette dressings. Drizzling some oil over vegetables just before you serve them will add visual and taste sparkle. Try it over asparagus or eggplant grilled on the barbecue. And, of course, crunchy bread dipped in olive oil is a slice of heaven.

But don&rsquot waste the extra-virgin oil in a skillet when you are frying food. For that, the light or extra-light olive oil will serve you better because it has a higher smoking point.

Bon appetit!