Olive oil

:For Popeye's girlfriend, see Olive Oyl.

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.

Related Topics:
International Olive Oil Council - Global - Production

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Classifying production

Olive oil is classified by how it was produced, by its chemistry, and by its flavor.

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All production begins by transforming the olive fruit into olive paste. This paste then malaxed to allow the microscopic olive droplets to concentrate, then the oil is extracted by means of pressure (traditional method) or centrifugation (modern method). After extraction the remnant solid substance, called pomace, still contains a small quantity of oil.

Related Topics:
Malaxed - Centrifugation - Pomace

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The several oils extracted from the olive fruit can be classified as:

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• Virgin means the oil was produced by the use of physical means and no chemical treatment. 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 (characterized as defects) and neutralize the acid content (free fatty acids). 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.

Quantitative analytical methods determine the oil's acidity, defined as the percent, measured by weight, of free oleic acid in it. This is a measure of the oil's chemical degradation — as the oil degrades, more fatty acids get free from the glycerides, increasing the level of free acidity. Another measure of the oil's chemical degradation is the peroxide level, which measures the degree to which the oil is oxidized (rancid).

Related Topics:
Quantitative analytical methods - Acidity - Free - Oleic acid - Glycerides - Rancid

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In order to classify olive oil by taste, it is subjectively judged by a panel of professional tasters in a blind taste test. This is also called its organoleptic quality.

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Grades on retail labels

The IOOC standards are complicated. The labels in stores, however, clearly show an oil's grade:

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• 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.
• Virgin olive oil 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.

Label wording

Olive oil vendors choose the wording on their labels very carefully.

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• "Imported from Italy" produces an impression that the olives were grown in Italy, although in fact it only means that the oil was bottled there. A corner of the same label may note that the oil was packed in Italy with 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" comes from olives 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" suggests that the essence was captured, but in fact means that the taste and acidity were chemically produced.
• "Lite olive oil" suggests a low fat content, whereas in fact it 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" gives the impression that extraordinary care went into the oil's production, whereas it is not clear that a manual harvest produces better oil than the common tree-shaking method.