Homeschool Science: Olive Oil Mill Tour

Another thing to love about homeschooling - lifelong learning for the entire family! This week, the girls and I enjoyed a tour of and talk about the olive mill at Figueroa Farms in the Santa Ynez valley. The mill doesn't typically give tours, but this was a special, educational program organized by a local foodie and led by Shawn Addison, the owner himself - in the height of harvest/milling season, no less!

Do YOU know what olive oil is made of?

Oh. Sure. (rolls eyes)

Olives.

Right.

But what else? I mean, what makes the OIL? You squeeze or mash an orange and what do you get? That's right. Orange JUICE. How about an apple? Right. Apple JUICE. It's not oily, and certainly wouldn't do you much good if you used it to keep onions from sticking to the frying pan. But olive oil? I always figured they pressed the olives, then added something or another to it, or treated it in some super special, secret manner to create the oil.

Turns out extra virgin olive oil, the be all and end all of olive oils, is nothing more than olives smashed to smithereens. There are lots of other factors, largely measured by chemistry labs, in determining whether the oil qualifies as extra virgin. But, basically, the olives are hand picked from any of a number of varieties of olive trees. They're poured into a hopper which delivers them to the mill through a variety of conveyer belts and chutes.

First, a beater of sorts separates any remaining leaves and sticks from the olives. Then the olives are dropped into an active bath, sort of like a jacuzzi for olives, our guide pointed out. The olives drop through one final grate to catch any final sticks and leaves, then pass to the grinding machine.

The whole fruit is ground - skins, meat and olive pit, too. Addison said only about 1 to 1.5 percent of the oil extracted from a batch with come from the pit. Its value in the process is its abrasiveness - crushed pits are devastating to the remainder of the fruit as it gets stirred by augers until its a green-brown pasty mess.

V pointed out the gray tubes I'd noticed along the route weren't actually colored gray. They were translucent, and we could watch the goo paste travel from the masher to the extractor. There, the paste drops into a centrifuge which spins at about 3000 rpm. The resulting juice, a mixture of water and oil, is then separated with a centrifugal decanter. The resulting oil is ready for your bread, salad dressing or sipping.

Yep, we sipped a few different olive oils before the girls resorted to spreading fingers full on their hands and nails, and finally their lips and one girl's face.

Levity.