We have an olive tree in our garden which has finally matured enough for a crop of olives. I've been watching the olives ripen from the window of my sewing room. Last week I picked some, they hadn't fully turned black (given the choice, I prefer to eat black olives rather than green olives) but I was worried that the birds would get into them and ruin them.
I started curing them (in the right hand jar) and today I noticed that there were more black olives on the tree so I picked more and set about curing them (the left hand side jars). The method I am using is the one from The Real Food Companion by Matthew Evans, simply immerse in fresh water, change the water every day and after ten days or so they will be ready for brining, which will take another three months.
The plastic bags (which are filled with water) are to keep the olives submerged in the water, you could use a plate but as I'm using jars, plastic bags are the simplest way to accomplish that. It was also recommended to taste one prior to curing, which I did, it was awful, but necessary because after the ten days is up, you need to taste another one to see if some of the bitterness has abated. I can report that it worked as the one I tasted this morning wasn't as bitter as the one I tasted ten days ago, its worth noting that the ones I did today didn't taste quite as bitter, probably because they are riper.