Green and black olives are essentially the same fruit harvested at different stages of ripeness; they both grow on olive trees ( Olea europaea).
Here's a breakdown:
-
Green Olives: These are picked before they are fully ripe, when they are still green and hard.
-
Black Olives: These are harvested when fully mature, after they have turned dark reddish, purplish, or black on the tree. However, many commercially available "black olives" are actually green olives that have been artificially ripened through a curing process.
The Curing Process:
Since olives are naturally very bitter, they are not edible straight from the tree. They must be cured to remove the bitterness. Different curing methods affect the final color and taste of the olives.
Green Olives Curing:
- Green olives are often cured using lye (sodium hydroxide) solutions. This process can be relatively quick.
- They are then brined (soaked in salt water) to ferment and further remove bitterness.
"Black" Olives Curing (Often Green Olives Artificially Ripened):
- Commercially canned "Ripe Black Olives" are frequently green olives that have been treated with lye and then exposed to oxygen (often through repeated washing and exposure to air) to darken them artificially. Ferrous gluconate, a black iron compound, is often added to stabilize the color.
- This process gives them a uniform black color and a milder flavor.
Naturally Ripened Black Olives Curing:
- True, naturally ripened black olives can be cured by brining, dry-salting, or oil-curing, often taking longer than curing green olives. This results in a more complex and intense flavor.
Summary Table:
| Olive Color | Harvest Stage | Curing Method | Flavor Profile |
|---|---|---|---|
| Green | Unripe | Lye solution and brine | Bitter, firm |
| "Black" | Artificially Ripened (Often Green) | Lye solution, oxygen exposure, ferrous gluconate (often) | Mild, uniform color |
| Black | Fully Ripe | Brining, dry-salting, or oil-curing | Complex, intense |
In conclusion, while both green and black olives grow on the same trees, they are harvested at different times and undergo different curing processes, resulting in different flavors and textures. Commercially available "black olives" are often artificially ripened green olives.
