How Olive Oil Is Made
The Mediterranean diet includes a lot of olive oil and the health benefits derived from it. You may be curious to know how olive oil is made, from tree to bottle. Here’s how:
Mediterranean olive trees start bearing fruit, olives, after about five years.
Olive trees have a very impressive lifespan. Some trees live and produce for several hundred years! The olive is a green drupe (fruit surrounding a single pit), and as it ripens, it turns black or deep purple.
Olives are harvested, using a tree-shaking device or by being hand-picked (labels often differentiate between the two), and the stems, leaves, and twigs are removed.
Olives contain the highest concentration of polyphenols, or antioxidants, for about two to three weeks as they ripen. Ideally they’re harvested during that time. The more ripe, the more oil an olive contains as well, but the best oil comes from olives that are a reddish color (not fully ripened).
Rollers crush the olives into a paste, which is then cold pressed and sent through a centrifuge device to separate the oil out.
The solid matter that remains is known as pomace and is often pressed again for oil that is classified as olive-pomace oil. For the most part, olive-pomace oil is used commercially, meaning that you won’t see it on your grocery store shelf.
The oil is refined in various ways to reduce acidity and to remove pesticides.
This process also removes chlorophyll and nutrients.
The processed oil is stored at about 65 degrees Fahrenheit before being bottled and shipped to market.