It has been a learning experience for me. I try to refine and expedite the process every year. It. is. a. lot. of. work.

I planted this mini-orchard (currently 14 trees) over the course of several years. At the beginning, I noticed that Grocery Outlet had olive trees mixed in with the fruit trees they usually have out front in the spring. Quality trees (Duarte) for dirt cheap. I bought a few every year for about 4 years, and then they stopped having them. :(

The varieties I have are Arbequina and Koroneiki, which are very small olives, but with high oil content. The first year I harvested (from about 8 tiny tees) I gleaned a coffee can full of olives. Hardly enough to warrant processing for oil. I decided to brine them for eating. Very tasty, although being so small, they were mostly pit.

The harvests grew larger in the following years as I added more trees and they grew larger. I experimented with various methods for grinding the olives. I tried a standard kitchen blender (smoked it). I tried an old hand-cranked meat grinder. It worked, but was extremely slow and tiring.

I was contemplating a heavy-duty meat grinder from Cabela's or similar, made for processing game meat. They are very expensive. Then I stumbled on an online post from someone who said they were using a heavy-duty garbage disposal to grind olives. A trip to HD and $125 later, I had a 1 1/2 HP garbage disposal. I mounted in an old kitchen sink on a stand, and it worked very well.

But grinding the olives is only the start of the battle. These are the basic steps to processing olives.
1) Grinding. This produces a thick paste.
2) Low speed mixing (known as malaxation or malaxing), which starts the process of separating the oil from the water and everything else.
3) Pressing, which produces a mixture of oil, water and sediment.
4) Racking, which separates the water from the oil due to gravity.
5) Filtering, which removes most remaining sediment.
6) Bottling (the fun part...finally).

I currently process such"
Grinding - the garbage disposal into a food-grade 5 gal. bucket.
Malaxing - I use my wife's Kitchenaid mixer on the slowest setting. It takes about 40 min. per bowl to separate the oil.
Pressing - I wrap a few scoops of the malaxed paste in cheesecloth, like a burrito. Grade 50 cheesecloth works best. Grade 10 (like from the grocery store) is too loose and open. Grade 90 is too tight. I press them using a standard 12-ton hydraulic shop press ($100-ish from Harbor Freight). I press onto a cookie sheet with a 3/4" hole in one corner. A bucket hung underneath catches the oil/water.
Racking - I bought a plastic cone-bottomed tank with a threaded fitting on the bottom, to which I attached a valve. I initially tried a 5-gal bucket with a valve, but got too much water in the oil due to the flat bottom.
Filtering - I first tried coffee filters, but it was way to slow. One drip every 30 seconds. I now use several (8-12) layers of cheesecloth which is quite fast and effective in filtering out sediment and even any remaining water.
Bottling - Out of the racking tank, through the filter funnel and into the bottle!

Last season, we gleaned 187 ounces of beautiful oil, not including waste from 14 trees. There is always some waste, as oil sticks to the buckets, filters, etc.

The harvest this year looks to be less (olive trees produce on new growth in alternate years) but they are nearly ready to pick. I can't wait to get started.

Of course, the commercial producers use millions of dollars worth of equipment to the same end. They don't press anymore, they use high-speed centrifuges to separate the water and oil. They don't pick by hand. They malax in huge vessels the size of tanker trucks. California Olive Ranch has a huge orchard and production facility just a mile from where I live.

But I think my oil is just as good as theirs ;)

Sorry to bore you...but I like sustainable olive oil.