Differences Between Virgin and
Extra-Virgin Olive Oil

Olive Oil Grading and Classification

by The International Olive Oil Council

"Virgin olive oil" denotes oil obtained from the fruit of the olive tree solely by mechanical or other means that cause no alteration or deterioration of the oil.

No heat, no chemical interaction, no solvents, no radiation, no microwaves!

Therefore, the oil must not have been subjected to any treatment other than that of mechanical expeller pressure, washing, centrifugation, and filtration.

The best oils, those called "extra-virgin," are cold-pressed, a chemical-free process that involves only pressure, which produces a natural level of low acidity.

Climate, soil, variety of olive tree and time of harvest account for the different organoleptic properties of different olive oils. "Organoleptic" properties refers to the oil's the flavor, bouquet and color. The term comes from the Greek organon (tool) and leptos (fine), and usually refers to the instant when all the senses are employed in a food's assessment.

Differences Between Extra-Virgin,
Fine Virgin, and Ordinary Virgin Olive Oil

Extra-virgin olive oils must have an acidity of less than 1 percent. The organoleptic properties must rate at least 6.5 on an Italian tasting panel's scale of 1 to 10. Virgin olive oils, on the other hand, may have an acidity between 1 and 2 percent. Its organoleptic values must score 5.5 or higher. There are other requirements for each of these designations, as well.

The International Olive Oil Council assigned different designations to virgin olive oil:

• Extra-Virgin Olive Oil is virgin olive oil that has a minimum organoleptic rating of 6.5 out of 10, and low acidity under 1%. It is the oil of the highest quality, and boasts a perfect, fruity taste, and with a color that can range from crystalline champagne to greenish-golden to bright green. Extra-Virgin Olive Oil can be used in endless ways in the kitchen, and in Italy it has been a traditional ingredient in everything from antipasti to desserts. It is best used raw in salads, in order to enjoy its real flavor. Because of the time-consuming process required to manufacture extra-virgin oil, and its limited production volume, true extra-virgin olive oils are expensive. Thus, any inexpensive olive oil labeled "extra-virgin" is probably not authentic.
• Beneath Extra-Virgin Olive Oil comes Fine Virgin Olive Oil. Like virgin oil, it is also cold-pressed. It has an organoleptic rating of 5.5 or more and an acidity of max 1.5 percent. Quality oils are obtained when the olives are crushed as quickly as possible, since any storage would trigger a fermentation process in the fruit, making the oil produced increasingly acidic and undesirable in both flavor and aroma.
• Semi-Fine or Ordinary Virgin Olive Oil is another virgin olive oil. It only has an organoleptic rating of 3.5 or more and acidity of max 3.3 percent. When properly processed, Ordinary Virgin Olive Oil maintains the purity of the fruit's flavor, aroma, and vitamins. The International Olive Oil Institute recommends using pure olive oil for frying, since the flavor of extra-virgin olive oil tends to break down at frying temperatures.

Testing to Determine Whether an Olive Oil is Extra-Virgin

Place a small quantity of the oil in a glass bowl and refrigerate it for a few days. If it becomes crystalline, the chances are good that it is a true extra-virgin olive oil. If it forms a block, it is most likely chemically refined oil that has had some first-pressed oil added to it.

How to Buy Olive Oil?

There are hundreds of extra-virgin olive oils on the market from different Italian regions, and most of them are quite good. But how do we choose one bottle over another? How many of us are buying a product because of its price or packaging rather than its content? Labels can say anything at all, and are often misleading embellishments or outright false statements.

Price
Often price is a determining factor in our willingness or reticence to buy a particular olive oil. There are cases in which a consumer pays a higher price only for the packaging, not for the oil's quality. While generally price is an indication of quality, it is not an absolute measure. It is important to remember that olive oil is a product of nature, so it follows the rule that mass production cannot reduce the cost unless it also reduces the quality.

Season
Olives picked early in the season yield a fruity olive oil; olives picked in the middle of the season yield an olive with harmonic flavor; and olives harvested late in the season yield a gentle olive oil. Some of us prefer fruity olive oils, others are partial to milder ones. There is no right or wrong: The only thing that matters is quality.

Of course different olive oils are better suited to different dishes, so that a fruity olive oil on a steamed fish might be a little excessive, and a mild olive oil on a sauté redolent with garlic would be overshadowed.

Storing
Olive oil should be stored in a closed container, away from heat or light. Correctly stored, good oil has a shelf life of 12 to 18 months. You do not need to store oil in the refrigerator. However, if you do, it should still be fine—just leave it at room temperature for half an hour, and it will return to its previous consistency.

OLIVE OIL STORAGE INSTRUCTIONS.

SUNLIGHT. Keep at dark for storage, avoiding any exposure to direct sun light.

HEAT. Optimum storage temperature is +18 °C to +20 °C (+64 °F to +68 °F). Refrigerating or freezing does not harm any type of olive oil. But olive oil expands about 2-4 % by refrigeration or freezing and may shatter the glass bottle if bottle head space is not sufficient to compensate the expansion.
Refrigeration or ambient temperatures less than +15 °C (+59 °F) may causes partial crystallization at extra virgin type olive oils. Crystallization effect is less in blends of refined olive oils.
This effect is harmless and when olive oil container stored at room temperature of maximum +25 °C (+77 ° F), when olive oil temperature exceeds +16 °C (+60 °F), olive oil crystallization disappears and returns to golden clear color without any quality loss. 

Virgin and Extra Virgin Oils must never exceed +25 °C (+77 °F). Otherwise nutritionally valuable vitamin E is degraded.

AIR. Oxygen inside air may cause olive oil to become rancid. This starts from the top surface where air exposure is continuous. This the reason the necks of the bottles are narrow, surface exposed to air is minimized. When the rest of container will not be used, say within a month, it is better to transfer the olive oil to a smaller container and fill till to half neck and seal the lid tightly to prevent air penetration.


FOREIGN ODOURS. Olive oil easily absorbs foreign odours and smells carried by air. You must keep olive oil in a tightly sealable container and tightly seal the container after every use and stow away from synthetic or natural odours, fuels, chemicals, exhaust gases, organic debris, etc.


CONDENSATION. Differences of temperature due to night and day, rainy days or climate changes may cause condensation of moisture in air on the walls of container as pure water droplets. When the container is tightly sealed, outside moisture shall not effect olive oil. However temperature drops by night may cause condensing of water droplets on outside of olive oil container. If container is tin, rust may start and if there is a paper label, paper may absorb the water and swell and deform and may partially peel off. The corrugated carton boxes containing olive oil containers can absorb the condensing moisture and become softer and not be able to carry the containers and may be easily torn by slight forces.
To avoid this situation, the ambient relative humidity must be less than 60% and cartons should be stowed about 10 cm (4”) above the ground on pallets and cartons should be covered with cloth or plastic in high ceiling spaces.

The History
The olive is a subtropical, broad-leaved, perennial tree which produces edible fruit. Its ancestor, Oleastro, dates back millions of year. Archaeological records indicate olives have been eaten for over 35,000 years, and that man has cultivated the tree for at least 6,000 years. The olive tree ranges in height from 10 to 40 feet, or more, and can attain a great age — some in the eastern Mediterranean are estimated to be over 2,000 years old.

The olive came from Asia Minor and spread along the coasts of the Mediterranean, in the area between the 30th and 45th parallels. About 6,000 years ago, in the Fertile Crescent — what is today Syria and Palestine — olives first began to be cultivated. The practice quickly spread to Crete, flourishing in the island's dry climate. Cretans became wealthy by exporting the oil and making lotions and cosmetics from it. An entire shipping fleet was made for selling oil to the Egyptians and the Greeks, carrying large quantities of oil in amphorae (vase-like jars) known as pithoi.

The first recorded oil extraction mill was in Palestine in 1000 B.C. Over 100 olive presses have been found in Tel Mique Akron, where the Philistinese first produced oil. These 100 presses managed to produce between 1,000 and 3,000 tons of olive oil per year.

The Tree
The wood of the olive tree resists decay, and when the top of the tree is killed by bad weather or human mistakes, a new trunk will grow back from the roots. Despite harsh winters and burning summers, the olive continues to grow and produce fruit. The branches are able to carry a large amount of fruit on their numerous twigs, which are so flexible that they sway with the slightest breeze but remain very strong.

Olive leaves are thick and leathery. Each leaf grows over a 2-year period and flowers bloom in late spring. They are small and white, grouped in loose clusters in the axels of the leaves. There are two different kinds of flowers: perfect flowers, containing both male and female parts, which are capable of developing into the olive fruits; and staminate flowers, male only, which contain the pollen-producing parts.

How Olive Oil is Made

Harvesting
Production of olive oil begins with the harvest, the timing of which is a major factor in the final product. The picking of the olives starts as early as September, when the olives are underripe and still green. They yield little oil, but their flavor is intense. These oils have the longest shelf life and are richer in sensory properties such as flavor and aroma. Oil from olives harvested early has a low percentage of acid and the characteristic deep green color typical of the Tuscan oils.

Harvests generally come between early November and let December. Some olives are harvested in the red-ripe stage and blended with the earlier harvested oil to create a more balanced product. In general, the oils from fruit harvested in the black-ripe stage are of inferior quality, containing more acid and less flavor.

The youngest green olives are hand-picked off the branches, whereas riper olives can be beaten or shaken down and collected beneath the trees. Since olives are delicate, the best oils are made from olives that are picked by hand or by machines that do not beat or bruise the fruit.


Milling and Pressing
Olives should be crushed within the first 24 or 36 hours of picking. If left to wait, the level of acidity rises, creating olive oil of poor quality. Just before being crushed, the olives need to be run through a washer to eliminate any remaining impurities. Generally the olives are crushed whole, without prior stoning in roller mills.

The simplest method of crushing olives is with a varying number of granite millstones. The olive paste obtained through milling is layered on nylon, or natural fiber, mats, called "fiscoli," which are stacked high, with metal disks between them. These mats of olive pulp are then subject to a great deal of pressure from a screw or hydraulic press. The liquid produced by the pressing drains through the mats and cylinder and is collected for the final separation.

This liquid is made up of water and oil that need to be separated from one another. The liquid is put through a centrifugal separator, where the rapid spinning eliminates all remaining water and all of the impurities from the oil.

After centrifugation, oil appears amber in color, with an opaque quality—a characteristic feature of superior oils. The more acidic the oil, the clearer and brighter it appears, and the worse it is for your health. Oils processed by anything but centrifuges and mechanical or hydraulic presses cannot be called virgin olive oil.