Labels such as virgin, extra virgin and pure are used to categorize olive oils according to their acidity.

Cooks have a variety of oils to choose from these days. Canola, vegetable and peanut oils are among the most highly visible brands advertised on television and stacked on grocery store racks. Olive oil has seen a surge in popularity as well. The only oil to be pressed from a fruit, olive oil is praised for its distinct flavor and light body. Olive oil is also quite versatile in the kitchen, substituting easily for most any other oil.

The use of olive oil is said to have originated in Syria where the first olive trees were cultivated. The uses of olive oil extended well beyond the kitchen. The oil was used as a fuel for lamps and also as anodyne for burns and wounds. Olive trees extended into the Mediterranean where the climate was highly conducive to their cultivation. Italy is perhaps best known for her olive oils and she counts among the major producers. Greece is famous for their Kalamata olives, and her inhabitants are the largest consumers of olive oil in the world. Spain, France, Portugal, Morocco, Tunisia, and Algeria also have important olive oil industries.

The cultivation of olives has produced over 900 varieties of olives from which to press oil. Olive trees are prorogated from cuttings. When the cutting has taken root under special care in the greenhouse, it is ready to be planted in the ground. Depending on the type of olives desired, anywhere from fifty to three hundred trees could be planted per acre. The first fruit will appear after four years, and the trees reach peak production between twelve and fifteen years. Young unripened olives are green with a smooth, tight skin. Mature olives are black with a wrinkled skin. Sizes range anywhere from the small Nicoise olive to the plump Kalamata.

The flavor of olive oil depends on the time at which the olives are harvested. According to the California Olive Oil Council, green olives picked before maturity produce a rich and fruity oil. The more mature the olive, the more mild the oil flavor, although the amount of actual oil produced upon pressing is much higher than with green olives. The type of olive also adds to the oil's flavor, but most oils tend to be blends of several varieties.

Olives are picked by hand and washed before being crushed under a stone mill or hammer. The result is a pate of crushed fruit, skins and pits, which contain valuable preservatives. In more traditional refineries, the pate is spread over mats that when pressed together allowing the liquid to escape from the solids. This method requires exceptional cleanliness in the mats. Olive oil not properly removed from the mats will turn rancid, souring an entire oil batch. More modern presses have come to rely on the centrifuge to separate the olive solids from the oil. Results of the first centrifuge may contain some residue of water or solids, which could taint the oil, so a second purifying centrifuge is performed. The oil is given time to rest before it is bottled for the consumer.

Labels such as virgin, extra virgin and pure are used to categorize olive oils according to their acidity. Virgin olive oil is the first pressing of the olives with an acidity level no higher than three percent. To receive the virgin label, however, the oil must not be further processed by heat or chemicals. Extra virgin olive oil is the first pressing of the olives with an acidity level no higher than one percent, and no heat or chemical processing. Both virgin and extra virgin olive oils are considered 100% unadulterated olive oil. Pure olive oil is extracted with heat and chemicals from the pulps, or solids, left behind after the first pressing. Virgin olive oils are said to have better flavor then pure olive oil, which is also less expensive.

Olive oils are typically used as a basis for oil infusions. The natural flavors of herbs, citrus and spice are extracted and infused into the oil. The new flavored oil adds accents to marinades, dressings, and sauces. The California Olive Oil Council considers the best infused oils to be the ones where the olives and additional extracts (citrus, herbs, etc.) are crushed together. Also, if virgin olive oils are used, the flavor is far superior than those made from low-grade oils.

Choosing an olive oil is much like choosing a fine wine. The oil's bouquet should smell like fruity olives. Its taste can range from light to heavy depending on the variety. There should never be a metallic flavor (indication of rancidity) or a heavy after taste (inferior quality). Choose oils on personal taste preference and the oils' expected uses. Grilled chicken might require heartier oil than delicate seafood. Never judge oil by its color. Producers can easily influence oil's color during pressing and it is no indication of quality.

Many cooks are looking to olive oil to fulfill many of their modern cooking needs. Olive oil is reported to reduce cholesterol levels making olive oil a healthy choice. Olive oil is not, however, lower in calories or saturated fat compared to other oils. One ounce of olive oil contains 251 calories, 28.4 total grams of fat, and 3.8 grams of saturated fat. Canola oil has 251 calories, 28.4 total grams of fat, and 2.0 grams of saturated fat. The forbidden butter contains 248 calories, 28.2 total grams of fat, and 17.6 grams of saturated fat per ounce