May 17, 2009 | Olive Oil |

"Cold Pressed" Olive Oil Extraction

Centrifuge made by PieralisiA very common marketing term that is thrown around quite loosely in the extra virgin olive oil world is "cold pressed."

The intent is to try to prove to the public that a producer's olive oil was not manipulated by temperature. Just so you know, we, along with most extra virgin olive oil producers, warm the olive paste to 26 degrees Celsius (79 F). This is common in quality-driven producers.

According to, "cold pressed" is an anachronistic and largely unregulated label description for olive oil. Fifty years ago when most oil was made in vertical presses, the paste was pressed to make olive oil and then mixed with hot water or steam and pressed again to remove more oil. This "second pressing" was not as good, as the heat evaporated some of the delicate flavors.

In reality, this method of making olive oil in vertical presses is outdated and risky. The paste is spread on fibrous mats that are practically impossible to sanitize. Metal discs are stacked on top and then alternated by mats and these discs. After a big stack is formed, the pressure is created and slowly squeezes the oil out. The oil tends to oxidize quickly and the fibrous mats contribute to microbial contamination.

The more modern approach to olive oil production is by centrifugation. There are two centrifugation methods used worldwide today. The first is a 2-phase system, which is what we use here at LMR. 2-phase means we separate the solids (olive husk) from the liquids (oil and water).

Three-phase process: raw oil on left; The second method is a 3-phase system, which is what Famila Zuccardi uses. A 3-phase system separates oil, water, and solids (olive husk). In both systems, the oil still has to go through a High Speed Separater Centrifuge to pull out the pure oil. The water (vegetable water) separated during the 3-phase system is sent to another Centrifuge to pull out any residual oil.

High speed separator clarifying raw oil Why are we so different? The advantage of a 2-phase system is to use the highly-concentrated nitrogen paste (olive husk waste) in our organic compost pile. This is where our organic and sustainable approach comes in. We never have to fertilize our vineyards or orchards with chemical fertilizers as a result of this naturally occuring by-product.

Dry olive husks from three-phase process stockpiled for compostingAs for Familia Zuccardi, they have two by-products left over. Dried olive husk and vegetable water with loads of nitrogen are at their disposal. The vegetable water is collected in a small reservoir outside the olive mill. When it comes time to irrigate, they mix the concentrated vegetable water with normal water and irrigate their entire property. Familia Zuccardi also has the pleasure of saying that they grow organic grapes and maintain their property sustainably.

There's a pattern here. . . sustainable and organic!

Until next time. . .

Posted by Jason Moulton


Kriegh Moulton's Gravatar
Kriegh Moulton
@ Apr 12, 2011 at 11:18 AM
Extremely well done. Concise, clear and evenhanded. Very informative!

Devonna Smith's Gravatar
Devonna Smith
@ Apr 12, 2011 at 11:19 AM
Very informative Jason. We miss you!!

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