Colour matters when it comes to olive harvesting, so you will need to learn how to distinguish the right olives to pick, depending on their colour! Now let’s get a bit more specific:
Green olives
All olives start out green. And immature. Typically, green olives are quite firm and have a longer shelf life, but they are also quite bitter. So they will need several months to mellow in flavor. These are the olives you need if you want to brine them. If you’re interested in producing oil from these olives, know that it’s going to be bitter, pungent and grassy.
Yellow-green to red-purple olives
As the olives start to ripen, their colour starts changing. They become softer, less bitter and less pungent. This is the ideal stage to harvest if you want to produce oil, since your olives now have close to a maximum amount of oil per dry weight. In fact, they are considered to be at their peak for olive oil production!
Black olives
The mature ones! Both edible (after they are water-cured) and full of oil! Their flavour is now mellow, and they have a high oil content, often described as “sweet oil”, since it’s even less bitter and less pungent.