Note: Due to miscommunication, this post was submitted late and thus scheduled late; rest assured, regular scheduling will resume on Sunday.
Back at my parent’s house in North County San Diego we have a lot of olive trees and every year they drop their fruit on the ground and make quite a mess. There is no sense in letting all of these olives go to waste so I looked into ways to turn them into a usable oil. It was surprisingly simple, just follow a few steps.
First the harvest. The olives are pretty small and there are a lot of them all over the tree making it way too labor intensive to pick by hand. The simplest way to do it is to lay a tarp on the ground, get a ladder and comb the branches with a garden fork or rake. Let the olives and leaves fall on the tarp then collect them all and pick the olives out.
Now that you’ve got a good amount of olives you’ve got to get the oil out of them. This is where industrial manufacturers use massive hammer mills and centrifuges. That’s a bit of an overkill for home production. First you need to crush the olives, to do this you can just get a strong bag, fill it with olives and go at it with a hammer. I tried a meat grinder and it worked OK but the pits jammed up the machine, a bag and hammer wont have that problem!
Once you have a pretty good pulp of olives you’ve got to mix them so that the oil can form large enough droplets to be pressed out. Don’t mix for much longer than 15 min because you’re adding oxygen to the oil and that will give it an undesirable flavor and color, but if you mix much less than that the oil won’t form large enough droplets.
Now for the pressing. It takes quite a lot of pressure to get the most out of this olive paste so I got a 20 ton bottle jack for a car, built a frame with a two plates and used the jack to press the olives. First spread the paste on burlap or cheese cloth, really any porous fabric that will allow the solids to stay in place and the liquids to flow. Then fold up the cloth, put it in the press and press. Collect all the liquid that comes out and pour it into bottles.
The liquid in the bottles will be about 90% water and 10% olive oil. Leave these bottles in a cool dark place for several weeks to give the oil plenty of time to settle out then pour off the oil on top and store for later, or enjoy now. It will taste very different from store bought oil, in a great way!