Naturally, extra virgin olive oil is packed with anti-aging antioxidants and hydrating squalene, making it superb for skin. Olive trees thrive best in areas 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.
Harvesting and Milling:
The olives are usually harvested in late October and early November. Olive harvesting is done by hand picking, hand shaking or mechanical harvesting.
After the olives are harvested, they are sorted according to their plumpness, state of ripeness and quality. They are then taken to the mill, stored for a short time, or a few hours to several days.
Some believe that olives should be milled within twelve hours of harvesting. However, the faster they are processed the better. Others keep them for a short period to prevent fermentation, but long enough for oil release.
- The olives are prepared for crushing by separating the leaves, stems, and twigs from the olives. Then rinsed in cold water in order to rid them of any dirt.
- The olives are then passed along a conveyer belt between rollers or continuous hammers, called the olive crusher. This hammer help crack the olive pits and break down the cells to release the oil.
- The next step is crushing the olives into a paste. In ancient times, the olives were crushed between huge cone-shaped stones as they turned slowly on a base of granite.
In the modern process, the milled olives travel from the mill into vast, while the slowly turning blades mash the olives into a homogenized paste.
Extraction and Pressing:
In the past, olives were pressed between layers of woven mats by large corkscrew-type presses. Today, the process is largely done by mechanical means using centrifuges to separate the olive pulp and water from the oil.
extra virgin olive oil
The term cold-pressing refers to the fact that the oil is extracted without heating the paste, furthering ensuring the purity of the oil. 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.
The solid material that remains after the extraction of the oil is called pomace, and it contains residual oil. Some manufacturers will use steam, hexane, as well as other solvents to squeeze more oil out of the pomace. This low-quality oil must be labeled as pomace oil.
ALL OLIVE OILS ARE NOT CREATED EQUAL
Olive oil is “graded” according to its flavor, color, aroma, as well as its acidity, which is the most important criteria for determining the grade.
The US is one of few countries that has not adopted the International Olive Oil Council (IOC) standards.
It has its own USDA olive oil grade standards, that were revised and became effective in October 2010. The hierarchy for our grades of olive oil is similar to the Australian standards.
While the written standards for the grades of olive oil can get quite complicated, very simply the differences correspond to the extraction and refining process.
Extra Virgin Olive Oil Skin:
Olive oil labeled Extra Virgin Olive Oil (EVOO) is considered the finest and fruitiest olive oil and is therefore also the most expensive. It can range from pale yellow to greenish-gold to bright green in color.
Remember that “extra virgin” is based on a series of requirements and that quality as well as taste may differ based on the manufacturer and the type of extra virgin olive oil.
The following factors can impact the taste of the olive oil:
- type of olive used
- soil conditions
- location where olives were grown
- weather during the “growing” and “harvesting” seasons
- the ripeness of the olives
- season/timing of the harvest
- harvesting method
- length of time between the harvest and pressing
- pressing technique
- packaging and storage methods.
Refined Olive Oil:
At the end of a typical mechanical pressing to create “Extra Virgin” or “Virgin” Olive Oil,” not all of the oil has been extracting from the olives. The remaining oil is extracted by a “refining” process that uses solvents and high heat to extract as much oil out of the olive as possible. This process is also used for seed and other oils.
However, the solvents and high heat make the oils odorless and tasteless. This process also allows producers to use olives that are not in the best condition.
Olive Oil: Olive oils labeled simply “Olive Oil” or “Pure Olive Oil” are blends of refined and unrefined oils. This grade of oil actually represents the majority of olive oil sold on the world market to the consumer.
Blends are made in proportions to create specific styles and prices. Olive oil grades in the US labeled as “Extra Light” would most likely be a blend dominated by refined olive oil. Other blends with more color and flavor would contain more virgin or extra virgin olive oil.
Pomace Olive Oil: This is the cheapest and poorest quality olive oil. Once the typical extraction of olive oil is complete, there is still quite a bit of olive pulp or pomace left which contains even more olive oil. The amount of oil contained in this leftover pomace, which consists of the solid remains of the olive including skins, pulp, seeds, and stems, cannot be extracted by pressing, but only through the combined use of chemical solvents (like Hexane) and very high heat.