Green Olives vs Black Olives: What Is the Difference?

Green olives and black olives grow on the same trees. The difference starts with when they are picked: green olives are harvested before they ripen, black olives when they are ripe or nearly ripe. After that, the curing method shapes the final colour, taste and texture just as much. Here is what the International Olive Council (IOC) says about each stage, and what it means in the kitchen.

It starts with ripeness

Olives change colour as they ripen, from leaf green to yellowish green, then to pink, violet and finally black. The IOC describes three harvest stages for table olives:

Stage	When it is picked	Typical result
Green olives	At full size, before any colour change, while the fruit is firm	Firm, crisp, often tangy and slightly bitter
Olives turning colour	When the colour begins to change, before full ripeness	Pink to brown-violet, firm
Black olives	Close to full ripeness, with the colour and oil content typical of the variety	Softer, fruitier, richer

Raw olives are very bitter because of a compound called oleuropein, so almost all olives need curing before they can be eaten. That is true of green and black olives alike; see are olives a fruit? for more on the fruit itself.

How curing changes the olive

Curing removes bitterness and preserves the fruit, and the method can matter as much as the colour.

• Spanish or Sevillian-style green olives: treated with a dilute lye solution, then fermented in brine. The IOC describes a fermentation at around 5% salt, which gives these olives their tangy flavour.
• Greek-style black olives in brine: ripe olives fermented in an 8–10% salt brine, which slowly removes the bitterness. The IOC notes that Greece commonly uses the Conservolea variety this way, that the olives may be packed with a little vinegar and a layer of oil, and that Kalamata olives are prepared similarly and are often slit.
• Dry-salted black olives: overripe olives layered with dry salt until they wrinkle like raisins; the IOC describes this as a Greek method using the Megaritiki variety.
• California-style “black” olives: picked while still green or turning colour, then treated with lye and darkened by exposure to air (oxidation). That is why canned ripe olives are uniformly black and mild.

So a black olive is not always a ripe olive, and colour alone tells you little about flavour. The label is the best guide: look for the variety, the words “naturally ripe” or “in brine”, and any ferrous gluconate (an additive used to fix the black colour of oxidised olives).

Taste and texture compared

	Green olives	Black olives (naturally ripened)
Texture	Firm, crunchy	Softer, meatier
Flavour	Sharp, grassy, sometimes bitter	Rounder, fruitier, often winey
Common examples	Halkidiki (Chalkidiki) and many Spanish-style olives	Kalamata, Conservolea, dry-salted throuba
Good for	Martini-style snacks, stuffing, bright salads	Salads, stews, tapenade, baking

Kalamata olives sit in between: they are harvested ripe, so they are deep purple to brown-black rather than jet black, and they keep a firm bite. Our guide to Kalamata vs black olives covers that comparison in detail, and Greek olive types introduces the main Greek varieties.

How do they compare nutritionally?

Both are mostly water and fat, and both are cured in salt, so they are salty foods. Exact values vary with the variety and the brine, so compare the nutrition labels of the jars you have. For figures on Kalamatas, see our Kalamata olives nutrition page.

Using them in the kitchen

Choose by job rather than colour. Firm green olives hold their shape in marinated olives and stuffed snacks. Fruity black or Kalamata olives suit a Greek salad, dakos and olive tapenade. The liquid in the jar is useful too: see olive brine for ideas.

Explore our Kalamata olives and the Kalamata olive collection.

Sources

• International Olive Council: Table olives (harvest stages and curing methods)

Green vs black olives: frequently asked questions