Olive Oil

Olive oil is a fat obtained from the olive (the fruit of Olea europaea; family Oleaceae), a traditional tree crop of the Mediterranean Basin. The oil is produced by grinding whole olives and extracting the oil by mechanical or chemical means. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps. Olive oil is used throughout the world, but especially in the Mediterranean countries and, in particular, in Greece where the largest consumption per person can be found.

Early cultivation

The olive tree is native to the Mediterranean basin; wild olives were collected by Neolithic peoples as early as the 8th millennium BC. The wild olive tree originated in Asia Minor in ancient Greece.

It is not clear when and where olive trees were first domesticated: in Asia Minor in the 6th millennium; along the Levantine coast stretching from the Sinai Peninsula to modern Turkey in the 4th millennium; or somewhere in the Mesopotamian Fertile Crescent in the 3rd millennium.

Ancient Greek olive oil production workshop in Klazomenai, Ionia (modern Turkey)

A widespread view exists that the first cultivation took place on the island of Crete. Archeological evidence suggest that olives were being grown in Crete as long ago as 2,500 BC. The earliest surviving olive oil amphorae date to 3500 BC (Early Minoan times), though the production of olive is assumed to have started before 4000 BC. An alternative view retains that olives were turned into oil by 4500 BC by Canaanites in present-day Israel. Until 1500 BC, eastern coastal areas of the Mediterranean were most heavily cultivated. Olive trees were certainly cultivated by the Late Minoan period (1500 BC) in Crete, and perhaps as early as the Early Minoan.The cultivation of olive trees in Crete became particularly intense in the post-palatial period and played an important role in the island's economy.

Recent genetic studies suggest that species used by modern cultivators descend from multiple wild populations, but a detailed history of domestication is not yet understood.

Production and trade

Ancient oil press (Bodrum Museum of Underwater Archaeology, Bodrum, Turkey)

Olive trees and oil production in the Eastern Mediterranean can be traced to archives of the ancient city-state Ebla (2600–2240 BC), which were located on the outskirts of the Syrian city Aleppo. Here some dozen documents dated 2400 BC describe lands of the king and the queen. These belonged to a library of clay tablets perfectly preserved by having been baked in the fire that destroyed the palace. A later source is the frequent mentions of oil in Tanakh.

Dynastic Egyptians before 2000 BC imported olive oil from Crete, Syria and Canaan and oil was an important item of commerce and wealth. Remains of olive oil have been found in jugs over 4,000 years old in a tomb on the island of Naxos in the Aegean Sea. Sinuhe, the Egyptian exile who lived in northern Canaan about 1960 BC, wrote of abundant olive trees.

Besides food, olive oil has been used for religious rituals, medicines, as a fuel in oil lamps, soap-making, and skin care application. The Minoans used olive oil in religious ceremonies. The oil became a principal 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.[citation needed] Olive tree growing reached Iberia and Etruscan cities well before the 8th century BC through trade with the Phoenicians and Carthage, then spread into Southern Gaul by the Celtic tribes during the 7th century BC.

The first recorded oil extraction is known from the Hebrew Bible and took place during the Exodus from Egypt, during the 13th century BC. During this time, the oil was derived through hand-squeezing the berries and stored in special containers under guard of the priests. A commercial mill for non-sacramental use of oil was in use in the tribal Confederation and later in 1000 BC, the fertile crescent, and area consisting of present day Palestine, Lebanon, and Israel. Over 100 olive presses have been found in Tel Miqne (Ekron), where the Biblical Philistines also produced oil. These presses are estimated to have had output of between 1,000 and 3,000 tons of olive oil per season.

Many ancient presses still exist in the Eastern Mediterranean region, and some dating to the Roman period are still in use today.

Olive crusher (trapetum) in Pompeii (79 AD)

Olive oil was common in ancient Greek and Roman cuisine. According to Herodotus, Apollodorus, Plutarch, Pausanias, Ovid and other sources, the city of Athens obtained its name because Athenians considered olive oil essential, preferring the offering of the goddess Athena (an olive tree) over the offering of Poseidon (a spring of salt water gushing out of a cliff). The Spartans and other Greeks used oil to rub themselves while exercising in the gymnasia. From its beginnings early in the 7th century BC, the cosmetic use of olive oil quickly spread to all of Hellenic city states, together with naked appearance of athletes, and lasted close to a thousand years despite its great expense. Olive trees were planted in the entire Mediterranean basin during evolution of the Roman republic and empire. According to the historian Pliny, Italy had "excellent olive oil at reasonable prices" by the 1st century AD, "the best in the Mediterranean", he maintained.

The importance and antiquity of olive oil can be seen in the fact that the English word oil derives from c. 1175, olive oil, from Anglo-Fr. and O.N.Fr. olie, from O.Fr. oile (12c., Mod.Fr. huile), from L. oleum "oil, olive oil" (cf. It. olio), from Gk. elaion "olive tree",[9] which may have been borrowed through trade networks from the Semitic Phoenician use of el'yon meaning "superior", probably in recognized comparison to other vegetable or animal fats available at the time. Robin Lane Fox suggests that the Latin borrowing of Greek elaion for oil (Latin oleum) is itself a marker for improved Greek varieties of oil-producing olive, already present in Italy as Latin was forming, brought by Euboean traders, whose presence in Latium is signaled by remains of their characteristic pottery, from the mid-8th century.






Olive Oil Manufacturing

The olive and the tree on which it grows have been revered since ancient times. Archaeological digs have unearthed evidence that olive trees existed on the island of Crete in 3500 B.C. The Semitic peoples were cultivating the tree's fruit by 3000 B.C. They particularly liked to use the oil of the olive to anoint the body during religious ceremonies, and to light their lamps. An ancient Hebrew law prohibiting the destruction of any olive tree is still obeyed.

By the time of the Roman Empire, olives were a mainstay of the agricultural economy. The Romans also used the oil to grease the axles of wagons and chariots. The Greeks traded it for wheat; the elaborately decorated clay pots that they used to transport the oil became part of the civilization's burgeoning art industry.

The olive tree is mentioned frequently in the Koran and in the Bible. Noah receives the message that land is near when a dove arrives at the ark with an olive branch in its mouth. Greek mythology associates the goddess Athena with the olive tree and credits Acropos, the founder of Athens, with teaching the Greeks to extract oil from the tree's fruit.

A member of the evergreen family, the olive tree features a gnarled trunk and leaves with a silvery underside. Its strong root system is perfect for penetrating sand, limestone, or heavy, poorly aerated soil. The trees thrive best in regions with rainy winters and hot, dry summers. Although it may take up to eight years before a tree produces its first harvest, a single tree can live for centuries.

Early oil producers pressed the olives by crushing them between huge cone-shaped stones as they turned slowly on a base of granite. Today, most factories employ hydraulic presses, exerting hundreds of tons of pressure, to separate the oil from the olive paste. Spain and Italy are the primary commercial producers of olives and olive oil. Greece is close behind them. However, California, Australia, and South Africa are emerging as leaders in the industry. Some wineries are planting olives to offset poor wine harvests. Ironically, olive trees were planted in California by missionaries in the 1800s, which by the turn of the century were producing an excellent grade of olive oil. However, the market demand was weak so the trees were uprooted and grape vines were planted in their place.

 In the late twentieth century, emphasis on good nutrition and a fascination with the so-called Mediterranean diet has resulted in a resurgence in the olive oil trade. Olive oil is touted as a mono unsaturated that is healthier for human consumption than corn and vegetable oils. The oil is also promoted as a dandruff reliever and, when mixed with beeswax, a homemade lip balm. In the late 1990s, the United States and Canada consumed olive oil at a yearly rate of 147,600 tons (150,000 metric tons). The demand often exceeds the supply, and during the 1990s prices rose significantly.

Raw Materials

 The primary ingredient of olive oil is the oil that is expressed from ripe olives. In the late spring, small flowers appear on the olive trees. Wind pollination results in the blossoming of the olives, which reach their
peak oil content approximately six months later. Thus, the olives are harvested from November to March, after they have progressed in color from green to reddish violet to black. It is often necessary to harvest olives from the same trees several times in order to gather olives at the same stage of maturation.


Since ancient times, workers have knocked the fruit from the trees with long-handled poles. The process has not changed significantly over the centuries. Modern poles resemble rakes. Originally, nets were spread under the tree to catch the falling olives. Many producers are now using plastic covers to cushion the fall and to allow for cleaner, faster gathering.

One quart (0.95 L) of extra virgin olive oil, the highest level of quality, requires 2,000 olives. The only added ingredient in extra virgin olive oil is the warm water used to flush away the bittemess of the olives, caused by the presence of oleuropein. Extra virgin olive oil contains not more than 1% oleic acid. Pure olive oil, that which results from the second pressing, is often mixed with extra virgin olive oil. The commercial, or non-edible, grades are put through a refining process that may leave traces of soda solutions and bleaching carbons.

The Manufacturing
Process
Collecting and grading the olives
1 After the ripe olives have been combed from the trees, they are picked over by hand to weed out unsound olives. The olives are divided into categories according to their plumpness, state of ripeness, and quality. Then the olives are taken to the press and stored for a short period of time, from a few hours to several days. The period is short enough to prevent fermentation but long enough to allow the olives to get warm so that they release their oil easily.
Washing and milling the olives
2 The olives are rinsed in cold water and then passed along a conveyer belt between rollers or continuous hammers. This machinery, often called the olive crusher, breaks down the cells and de-stones the olives. Depending on the resiliency of the olives' skin and the stage of maturation, it may be necessary to pass the fruit through the mill a second time.
Creating an olive paste through malaxation
3 In ancient times, the olives were mashed into a paste with a simple mortar and pestle. This principle was expanded upon until the stone mortars were large enough to require slaves or pack animals to operate them. In the modern process, the milled olives travel from the mill into vats in which slowly turning blades mash the olives into a homogenized paste.
Cold-pressing the olive paste to extract the oil
4 The oil is extracted by loading the paste into a hydraulic press. The olive paste is evenly spread over hemp pressing bags or disks covered with synthetic fibers. Each bag or disk is covered with approximately 9-13 lb (4-6 kg) of paste. Between 25 and 50 bags or disks are stacked onto a press plate. Plate guides are inserted at intervals of five to six bags. The plates serve to maintain the balance of the stack and to distribute the pressure evenly. A piston pushes up against the stack, and the oil seeps slowly through the pressing bags to attached tubes. The solid material remains inside the pressing bags.
5 The term cold-pressing refers to the fact that the oil is extracted without heating the paste, furthering insuring the purity of the oil. The oil that is expressed is a reddish mixture of the oil and the inherent vegetable water. This is the oil that receives the appellation of "extra-virgin" olive oil. The paste is removed from the bags and run through several more presses to obtain the lesser grades of oil that remain.





Separating the oil from the vegetable water
6 Originally, the oil and water mixture was stored in vats until the oil rose to the top and was skimmed off. Some fermentation was inevitable, affecting the taste and smell of the olive oil. Today, the separation is accomplished swiftly by pumping the mixture into a centrifuge. The centrifuge is comprised of a rotating drum and an auger that are spun on the same axis at great speed. Because the oil and the vegetable water are of differing densities, the centrifuge forces them apart and into separate receptacles.
Storing and packaging the oil
7 The oil is stored in underground vats until it is ready to be shipped. Then the oil is canned or bottled on an assembly line. Cans or dark-tinted bottles will keep the deep-green color of the olive oil intact. Oil placed in clear-glass bottles will fade to a yellowish-green. However, the flavor is not affected.
8 In many cases, olive oil distributors purchase the olive from the producers and rebottle it. Packaging has become more ornate as the popularity of olive oil has grown. It is not unusual to purchase olive oil in unusually shaped bottles topped with netting or rope. Some packagers also hire professional artists to design their labels.


Do Olives and Olive Oil Have the Same Health Benefits?


When I was growing up, there were only two kinds of olives at the grocery store: green olives stuffed with pimentos and pitted black or “ripe” olives that you could wear on the tips of your fingers until your Mom made you stop playing with your food.
Today, of course, most grocery stores have entire olive bars, with all kinds of exotic varietals—everything from the tiny brown Nicoise to the giant, bright-green Cerignola, to the shriveled black Morrocans.
But “are they all the same nutritionally?” asks Grace. “Or are some types particularly good for you?” Meanwhile, Tania wonders how olives compare to olive oil in terms of health benefits.
Do Olives and Olive Oil Have the Same Benefits?
Both olives and olive oil are promoted as healthy foods primarily because they are high in monounsaturated fats. Cultures whose diets are rich in this type of fat tend to have lower rates of heart disease, cancer, and obesity—even when their total fat consumption is on the high side. In fact, some researchers theorize that monounsaturated fats might be slightly less “fattening” than other types of fat because the body metabolizes and stores them differently. Monounsaturated fats also seem to be less likely to contribute to clogged arteries and heart disease.
The Differences Between Olives and Olive Oil
Here’s one big difference between olives and olive oil: Oil is virtually 100% fat, while whole olives are only about 20% fat. As a result, a serving of olive oil (1 tablespoon) contains 120 calories while a serving of olives (about 10 medium) has only 40.
There are a few other distinctions:

Olives, which have to be cured or pickled in order to be edible, usually contain a lot of sodium while olive oil is virtually sodium free.

The curing process removes a lot of the polyphenols in olives whereas these are largely preserved in extra virgin olive oil. (Polyphenols are phytonutrients thought to protect against disease.)

Whole olives provide some fiber; olive oil does not.

Some olives are processed with natural fermentation, meaning that they would be a source of beneficial bacteria; olive oil is not.
As you can see, olives and olive oil each have pros and cons. But it’s a little silly to try to compare them because they’re really not interchangeable. You’re not going to sauté your spinach in a handful of olives and you’re probably not going to have a tablespoon of olive oil as a snack. Suffice it to say that olive oil is one of the healthiest oils you can choose and olives make nutritious snacks and condiments.

What’s the Healthiest Type of Olive?


I’ve written previously about the best types of olive oil to buy. But what are your best choices when you belly up to the olive bar?
The concentration of oil and polyphenols varies according to the variety of olive and the degree of ripeness. Green olives, which are picked before they ripen, tend to be higher in polyphenols. Black olives, which are allowed to ripen on the tree, generally have higher oil content. Both ripe and unripe olives are good sources of iron, copper, and vitamin E.

How are Olives Processed?

As I said earlier, you can’t eat olives straight off the tree—even if they are “ripe.” Raw olives are hard and bitter. To make them edible, they are pickled in brine, or cured in salt or oil. The curing process removes bitter compounds (some of which are those healthy polyphenols), softens the fruit, and imbues them with flavor. It also imbues them with a fair amount of sodium.

Which Olives Have the Least Salt?

The amount of sodium in processed olives depends on their curing process. Unfortunately, detailed nutrition information may be hard to come by at the olive bar. In my experience, the big Cerignola olives are among the least salty varieties. And as a general rule, black olives will have about half the sodium of green olives.
If you’re very salt sensitive, you might want to skip the bulk olives and stick with olives in jars, which have nutrition facts labels. Here, too, your options have increased. In addition to the classic green-with-pimiento, even a modestly-stocked grocery store is likely to carry kalamata, Seville, and maybe even some oil-cured olives in jars..

Olives and Acrylamide

One last tip: As much fun as they are to wear on your fingers, some canned black olives have been found to be quite high in acrylamide. Since acrylamide has not been detected in other kinds of olives, it probably has to do with the way canned black olives are processed.
I talked about the potential dangers of acrylamide in a previous article. While I personally don’t think you need to worry that much about acrylamide exposure (especially when there are so many other things to worry about), that information might change how often you choose to indulge in canned black olives. If you like that style of olive (slightly sweet and fleshy), try ripe Cerignola instead. They’re even tastier.
What’s your favorite way to enjoy olives? Share it below in Comments or post it on my Nutrition Diva Facebook Page. And don’t forget to sign up for my free weekly newsletter, which includes more tips, recipes, and answers to listener questions.

Have a great week and remember to eat something good for me!