Filtered vs. Unfiltered Olive Oil: What Is the Difference?
You may have seen labels in the grocery store proclaiming that olive oil is “filtered” or “unfiltered.” So what exactly is filtering, and is it good or bad to filter olive oil? Here is what you need to know about filtered vs. unfiltered olive oil:
Why Is Olive Oil Filtered?
To understand why filtering is used, we need to understand how extra virgin olive oil is harvested and extracted. First, the olives are picked off the olive trees and then washed and cleaned to get rid of dirt and debris. Then, the olives are crushed to form a thick paste and slowly kneaded to start separating the oil and water from the flesh of the olives. Next, the mixture is put through at least one centrifuge (and sometimes two) in order to separate the olive oil.
When the olive oil comes out of the centrifuge, it is technically ready to use. However, this olio nuovo does still have water and olive fruit particles suspended in the oil, which gives it a cloudy or hazy appearance. The olive oil often undergoes a separate step of production to remove these particles, which improves the appearance of the olive oil and also prolongs the shelf life.
The oil may be filtered, which involves passing the oil through a medium — such as cellulose pads or diatomaceous earth — in order to remove the particles. It is important to note that this is a physical process, not a chemical one, and thus does not change the qualities of the extra virgin olive oil at all. It simply removes the particles and results in a clearer oil.
The oil may also be racked, or stored in large stainless steel containers for a certain amount of time. Over time, gravity will cause the olive fruit particles to drift to the bottom of the olive oil, separating them naturally. The oil may be transferred between different drums, becoming clearer and clearer with each transfer.
Both filtering and racking have their place in the olive oil world, and we actually use both at Brightland. Filtering is faster, but more labor- and material-intensive, so we usually do it for only a portion of each harvest so we can get it to customers as quickly as possible. Then, we rack the rest of the olive oil and let gravity separate the sediment for us. Either way, we get a great looking and tasting olive oil that is up to our quality standards.
Filtered vs. Unfiltered Olive Oil
At this point, you are probably wondering what the difference between filtered and unfiltered olive oil is. The most obvious difference is the appearance. Filtered olive oil is transparent while unfiltered olive oil is cloudy and more opaque. Many people find the appearance of filtered olive oil more aesthetically appealing.
Some people claim that unfiltered olive oil tastes fruitier than filtered olive oil. However, so many different factors go into the taste of an olive oil that any assessment of the flavor is often subjective. Furthermore, the taste of unfiltered olive oil will change more quickly over time because the particles left in the oil start to ferment, which will eventually alter the taste of the olive oil if you do not use it up fast enough. An unfiltered olive oil that tastes fruity right now might not be the same a few months down the road.
Speaking of fermentation, unfiltered olive oil does have a shorter shelf life than filtered olive oil due to this aspect. Unfiltered olive oil will last about 12 months, as compared to 18-24 months for filtered or racked extra virgin olive oil. For olio nuovo, which is extremely fresh, that shelf life is closer to four months. So if you are purchasing unfiltered olive oil, you need to have a plan to use it up relatively quickly before it goes off. (Learn more about the different types of olive oil here.)
We hope this answered your questions about filtered vs. unfiltered olive oil. To learn more about how olive oil is made, then browse our guides. If you would like to see what olive oils we offer, then browse our selection of California extra virgin olive oil online.