A topic we field frequently from consumers, chefs and family members: unfiltered versus filtered extra virgin olive oil. What’s the difference? Do we filter our oil? (No.) Which tastes better? (Our master miller, Bob Singletary, will tell you unfiltered oil does.)
Basically, filtering involves putting the oil through different materials, or filter aids, to help remove the olive fruit particles and other solids from the oil. Filters sheets, in the words of one filter supplier, are “essentially a maze of paper fibers” that trap the particles.
Instead of filtering, we remove those particles and solids with the help of Mother Nature – namely gravity.
Here’s how. After we crush the olives, the resulting olive paste is sent to high-speed centrifuges where the oil is separated from the particles, solids and water.
The remaining fruit particles – similar to pulp in orange juice – can enhance the taste and flavor of the oil. That’s what helps make our Limited Reserve extra virgin olive oil taste so fantastic. We bottle that oil immediately, without letting it go through the natural settling process. But, over time, those same fruit particles eventually ferment. Consequently, our Limited Reserve is dated on the bottle to be used more quickly than our other oils.
We pump the oil into large storage tanks housed inside a temperature-controlled room. Inside the tank, the oil is allowed to settle for a few months. The particles are heavier than the oil and naturally drop to the bottom of the tanks. We then move all of the settled oil to a clean storage tank, while leaving the solids and sediment at the bottom of the original tank for removal. This process is called “racking.”
We’ll move the oil from tank to tank periodically. And, depending on the olives harvested in a particular season, the racking process can occur several times. Typically, by around March the sediment has been removed and the new oil is ready to be shipped. (The oil made from the olives we harvested last fall, for example, will be available soon.)
The most noticeable difference between an unfiltered and a filtered oil is appearance. The unfiltered oil may look a bit cloudy, because of residual particles that weren’t removed through gravity in the settlement tank. Once the oil has been fully racked, however, the lower concentration of remaining fruit particles no longer has an adverse effect on the oil’s lifespan or quality.
Which tastes better – unfiltered or filtered oil? Some people say filtering has little effect on taste.
Master miller Bob Singletary would disagree. “If the oil is cold or not at the perfect temperature, the viscosity of the oil is thick and the filter aids pull a lot of the flavor profiles from the oil,” Bob tells us. “The filtration materials have the ability to strip many of the good flavors of the oil. Our process of allowing the solids to naturally settle and then removing them ensures all the flavors are maintained.”
Your friends at California Olive Ranch