1. Determine the stage of ripeness of the olives for the oil.
This is a bit of artwork. Different stages of ripeness will result in differences in taste and quantity. Green olives will have less oil, though that oil should keep very well. Dark, very ripe olives will produce a sweeter, better-tasting oil that would be great for eating for salad or mixing without cooking.
Then there is the blend where both green and black ripe olives are used together. This results in a mix of both and considered to be the best between great taste, quantity and storage life. We are using this option, as it is also the simplest to just pick all of the olives at this stage — some are dark, some are green — and we are done with it!
2. Rinse the olives, and sort out and remove contaminants like twigs and other stuff that should not be ground up.
3. Grinding: At the home scale, the recommended approach is to use a meat grinder.
All of the olive is ground up, including the pit. Also note that olives, even when they are ripe, are hard like golf balls. For our first grinding attempt, we started off using our Kitchen Aid mixer with the meat grinder attachment with the course meat grind screen installed. The mixer jammed within the first minute after with less than 1 cut of paste made.
After unjamming the mixer, we made a number of attempts to make the grind process less harsh, but to no avail. We simply needed a much more powerful meat grinder. So, off to the store we went for the largest home meat grinder we could get.
It worked great. We do have to be careful when feeding olives into the unit, to not overfeed, and allow the olive pits to work through the grind process. The olive meat tends to get mashed through quickly, The pits, however, tend to back up against the screen and take a bit longer to get chopped up and push through.
The mash looks like dark guacamole after it comes out of the mixer. We rerun the mash though the mixer with the big screen plates two more times. The course screen is then removed and the fine screen is installed and the mash is run a few more times until it is like guacamole — a nice and soft texture.
We are still in a learning curve for the next two steps...
4. The mash has to be slowly mixed — for 30 minutes or more, a process called malaxation.
This enables the oil droplets to join and pool prior to pressing. It has been a challenge to just leave the mixer on low speed and leave it for such a long
periods of time.
5. Pressing: Olive oil presses on the internet tended to be very expensive, especially as we only have three trees, and for us this is a very small-scale hobby operation.
So, I designed and built my own press based on a number of ideas and images viewed on the internet.
The press turned out quite nice and functions great. It even cost less than half what I could buy on the internet, if I count all of my time for free — design, shopping for materials and assembly. I do have fun designing and then building my own gizmos, so I should have to deduct the entertainment value from the costs.
The internet folks do not expressively advise you on the details of how to press the mash to get the oil. Many sites show them packing the mash in thin layers, separated by pieces of some sort of plastic and then pressing it. Well, we did that using thin plastic cutting board strips, and the mash just squished out.
What they do not discuss well are the synthetic fiber filter mats which hold the mash and allow the liquids to flow out. We are still in the experimental stage, sourcing and trying different materials to optimize this step. The ancient methods used “baskets,” which the olive and or olive paste was put in, and then squished. Synthetic fibers mats are used now because they can be much simply cleaned and then used again as needed.
We expect much better results as we continue our experiments on what are the best filter materials we can find.
In conclusion, we have learned a great deal and we still have plenty more to go. It has been lots of fun. Making olive oil to eat essentially does not cost anything and has turned out well.
Should you choose to dive into making olive oil, understand there is much to learn, there is a lot of art in finding what is your preferred versions, and do not forget that you will spend much more than you expect.