- For Popeye's girlfriend, see Olive Oyl.
In agriculture, olive oil is an oil extracted from the fruit of the European olive tree (Olea europaea L.), which originated in the Mediterranean area. It is used in cooking, cosmetics, and soaps. Olive oil is regarded as a healthy dietary oil because of its high content of monounsaturated fat.
Grades and classification
The International Olive Oil Council (IOOC) sets standards of quality used by the major olive oil producing countries. It officially governs 95 percent of global production, and holds great influence over the rest. IOOC terminology is precise, but it can lead to confusion between the words that describe production and the words used on retail labels.
Olive oil is classified by how it was produced, by its chemistry, and by its flavor:
Production. How was it made? All production begins by applying physical pressure at room temperature to the olive fruit, which extracts oil and leaves a substance called pomace.
- Virgin means the oil produced at room temperature and only using pressure—in other words, with no chemical treatment. Marketing materials refer to cold pressed or mechanically pressed, which mean the same thing. The term virgin oil referring to production is different than Virgin Oil on a retail label.
- Refined means that the oil has been chemically treated to neutralize strong tastes and remove much of the acid content. Refined oil is commonly regarded as lower quality than virgin oil; the retail labels extra-virgin olive oil and virgin olive oil cannot contain any refined oil.
Olive-pomace oil means oil extracted from the pomace using chemical solvents—mostly hexane—and by heat.
Chemistry. What is in it? Quantitative analytical methods determine the oil's acidity, defined as the percent, measured by weight, of oleic acid in it. In Italy, peroxide levels are also measured.
- Flavor. How does it taste? The oil is subjectively judged by a panel of professional tasters in a blind taste test. This is also called its organoleptic quality.
Grades on retail labels
The standards are complicated. The labels in stores, however, clearly show an oil's grade:
- Extra-virgin olive oil comes from the first pressing of the olives, contains no more than 0.8% acidity, and is judged to have a superior taste. There can be no refined oil in extra-virgin olive oil. Extra-virgin oil typically has a noticable green color.
- Virgin olive oil is also cold-pressed, with an acidity less than 2%, and judged to have a good taste. There can be no refined oil in virgin olive oil.
- Olive oil is a blend of virgin oil and refined virgin oil, containing at most 1% acidity. It commonly lacks a strong flavor.
- Olive-pomace oil is a blend of refined olive-pomace oil and possibly some virgin oil. It is fit for consumption, but it may not be called olive oil. Olive-pomace oil is rarely found in a grocery store; it is often used for certain kinds of cooking in restaurants.
- Lampante oil is olive oil not used for consumption; lampante comes from olive oil's ancient use as fuel in oil-burning lamps. Lampante oil is mostly used in the industrial market.
While it would be unfair to describe them as deceptive, olive oil vendors choose the wording on their labels very carefully.
- "Imported from Italy" sounds like the olives were grown in Italy, but in fact only means that the oil was bottled there. A corner of the same label may note that the oil was packed in Italy using olives grown in Spain, Italy, Greece, and Tunisia. Since Spain produces nearly half of the world's olive harvest, it is likely the oil "imported from Italy" was grown in Spain.
- "100% Pure Olive Oil" sounds like a high-end product, but in fact is often the lowest quality available in a retail store: better grades would have "virgin" on the label. Having said that, 100% pure olive oil might be perfect for baking and frying, since high heat can destroy the rich flavor of extra-virgin oil.
- "Made from refined olive oils" sounds like the essence was captured, but in fact means that the taste and acidity were chemically produced.
"Lite olive oil" sounds like it has a low fat content, but in fact refers to a lighter color. All olive oil—which is, after all, fat—has 120 calories per tablespoon (33 kJ/ml).
- "From hand-picked olives" sounds like extraordinary care went into the oil's production, but it is not clear that a manual harvest produces better oil than the common tree-shaking method.
The International Olive Oil Council is an inter-governmental organization based in Madrid, Spain that promotes olive oil around the world by tracking production, defining quality standards, and monitoring authenticity. More than 99% of the world's olives grow in nations that are members of the Council. Current member countries are Algeria, Croatia, Egypt, the EU, Iran, Israel, Jordan, Lebanon, Libya, Monaco, Morocco, Serbia & Montenegro, Syria, and Tunisia.
The United States is not a member of the IOOC, and the United States Department of Agriculture does not legally recognize its classifications (such as extra-virgin olive oil). The USDA uses a different system, which it defined in 1948 before the IOOC existed. The California Olive Oil Council, a private US trade group, is petitioning the Department to adopt terminology and practices that shadow the IOOC's rules. 
Among global producers, Spain leads with more than 40% of world production, followed by Italy and Greece. Much of the Spanish crop is exported to Italy, where it is both consumed and repackaged for sale abroad as Italian olive oil. Although boutique groceries sell high-quality Spanish olive oil at a premium, Italian olive oil has the popular reputation for quality.
Global olive oil market
The main producing countries in 2003 were: 
Olive oil production
Traditionally, olive oil was produced by beating the trees with sticks to knock the olives off and crushing them in stone or wooden mortars or beam presses . Nowadays, olives are ground to tiny bits, obtaining a paste that is mixed with water and processed by a centrifuge, which extracts the oil from the paste, leaving behind pomace.
In the United States, producers of olive oil may place the following health claim on product labels:
Limited and not conclusive scientific evidence suggests that eating about two tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil. To achieve this possible benefit, olive oil is to replace a similar amount of saturated fat and not increase the total number of calories you eat in a day.
This decision was announced November 1, 2004 by the Food and Drug Administration after application was made to the FDA by producers. Similar labels are permitted for walnuts and omega-3 fatty acids which also contain monounsaturated oil.
Olive oil in history
Historically, olive oil was used for medicines and as a fuel in oil lamps.
Olive oil was a central product of the Minoan civilization, where it is thought to have represented wealth. The Minoans put the pulp into settling tanks and, when the oil had risen to the top, drained the water from the bottom. It was also very common in the cuisine of Ancient Greece and classical Rome.
Used as a medicinal agent in ancient times, and as a cleanser for athletes (athletes in the ancient world were slathered in olive oil, then scraped to remove dirt), it also has religious symbolism related to healing and strength and to "consecration" -- God's setting a person or place apart for special work. The Catholic and Eastern Orthodox Churches use olive oil for the Oil of Catechumens (used to bless and strengthen those preparing for Baptism), Oil of the Sick (used to confer the Sacrament of Anointing of the Sick), and olive oil mixed with a perfuming agent like balsam is consecrated by bishops as Sacred Chrism, which is used in conferring the sacraments of Confirmation (as a symbol of the strengthening of the Holy Spirit) and Holy Orders (by which deacons, priests and bishops are made), in the consecration of altars and churches and, traditionally, in the "consecration" of monarchs at their coronation.