A number of parameters are used to judge the quality of olive oil, and most nations in the world are members of the International Olive Oil Council, which has tough standards for olive oil labeling that will provide insight into the taste as well. Unfortunately for American consumers, the United States does not belong to the council, and therefore American labels may be deceptive. Ideally, you should be able to taste an olive oil before purchasing it to judge its quality, but if this is not possible, there are a few things to look for which will help you make an informed decision.

The best olive oil tends to come from hand picked olives which are cold pressed, and the highest quality pressing is the first pressing. Hand picked olive oil ensures that no bad olives were mixed into the batch to taint the flavor of the oil, and also that leaves, twigs, and detritus were not mixed in with the olive press. Because hand picking takes time, olive oil made from hand harvested olives will be significantly more expensive. Cold pressing, without the use of heat, protects the complex flavors of the olive oil, while the first pressing is lowest in acid, and will have the most well developed, intense, olive oil flavor. Avoid refined and otherwise processed olive oils at all cost.

If possible, buy olive oil fresh. If you live in a olive oil producing region, you can often take decanters directly to the olive press for the best oil. If this is not an option for you, insist on olive oil with a production date; although olive oil stores well, it tastes better fresh. Furthermore, the olive oil should be of an even color, with no clouding, unless the weather is cold, and it should be stored in stone, ceramic, or glass. Plastic will leach unpleasant flavors into the olive oil. The olive oil should be stored in a cool, dry, dark place to prevent it from going rancid. If you live in a warm area, purchase olive oil in small amounts and use it quickly.

Taste, of course, is the best way to judge olive oil. Stores which supply fine olive oils will usually allow their customers to taste. Start by smelling the olive oil; it should smell like rich, fruity olives, with a faint hint of pepper. Examine the color for clarity, but do not put too much emphasis on what color the olive oil is, as different regions produce different colored oils. Next, taste a small amount, rolling it around your mouth before allowing it to slide down your throat. The oil should taste clean, rich, fruity, and strongly peppery. Truly high quality oil will have an intense bite, although this will mellow with time in storage. If the oil tastes buttery or otherwise “off,” it may be rancid, and should be avoided.