Color indicates ripeness
All olives start out green. A green olive is an unripe olive. It doesn’t mean it’s not a tasty olive if it’s picked and cured at that stage, but in the same way a ripe fruit will be more luscious and flavorful, a green olive is going to have less succulence, less flavor than a ripe olive. As olives ripen they turn colors. Different olives turn different colors but in general the progression is from green to brown to purple to black.
Go for hand picked
There are machines that shake olive trees, the fruit falls, and people pick it up. If this sounds slightly horrifying and a recipe for bruised fruit, it is. Bruising harms olives and their flavor the same way it does apples or pears. Hand picking is the way to go when you want great olives.
Salt cured: not optional!
You can’t eat olives right off the tree. They need to be cured. For thousands of years the recipe for the cure has been simple: sea salt. Salt draws the bitterness out of olives and softens them. In the last century lye—yeah, the same ingredient in Little House on the Prairie soap—has been used with industrially cured olives. It shortens the cure from months to days. The time savings come at a price in flavor, though. Lye creates a metallic, chemical aftertaste that mars the flavor.
Brine cured v. dry cured
The salt can be used with water in a brine or not. The two techniques create two very different olives. Brine cured olives are the most common ones you find. They are the plump, smooth olives you know, packed in liquid. Dry cured are very wrinkly and shriveled and have no liquid. Most dry cured olives are black, it’s a technique often reserved for the ripest olives.
Pits are it
Removing pits mechanically invariably causes the olive flesh to suffer. That’s why all the best olives you can buy will have pits and, while they are a bit more work, they make the best tasting table olive.
When I’m serving olives I take three tips from all the Sicilians, Greeks and Spaniards I’ve met, the ones who eat olives regularly. First, rinse the olives. Second, douse them with some good extra virgin olive oil. Third, add something fun: some fresh thyme leaves, a bit of lemon zest, a pinch of cumin. Those steps, combined with serving olives at room temperature, make a huge difference in flavor.