The only difference between a green and a black olive, however is the ripeness of the fruit, where a green olive is actually an unripened fruit
Rachel Zammit Cutajar
Out of the hundreds of different varieties of olive tree some are very similar with only DNA fingerprinting separating the types of olive, however some others differ tremendously with fruit varying in size, oil content, taste, chemical characteristics and ripening time among others.
When it comes to differences in olives, most people can only say that some are green while others are black. The only difference between a green and a black olive, however is the ripeness of the fruit, where a green olive is actually an unripened fruit.
Green olives are usually pitted and often stuffed with various fillings including pimentos, almonds, anchovies, jalapenos, onions or capers, while black olives are more often sold with their pit, though pitted varieties are also available.
Cultivated for over 6,000 years the olive is a mark of the Mediterranean where it typically grows in climates of relatively mild winters and hot dry summers.
Straight from the tree the olive is bitter and inedible and requires curing, usually in lye brine or salt. The taste of olives is affected not only by their variety but by ripeness and curing time. Heat also causes the olive to go bitter so they are best added to hot dishes at the end of cooking.
Cerignola - An enormous olive sold either green or black. When green it has a mild and vegetal flavour though when it turns black the flesh is softer and sweeter and is much easier to pit.
Gaeta - A small brownish black olive that can be hard to pit but the flavour, which is reminiscent of nuts, is worth the effort.
Kalamata - A plump, purplish black olive that grows in Greece. It is a good option for recipes that include black olives.
Manzanilla - This Spanish olive is most available at supermarkets. It is generally pitted and stuffed with pimentos or garlic. They are often used in martinis.
Moroccan oil-cured - These shrivelled black olives are somewhat bitter and best used in cooking rather than for snacking.
Nicose - A small, purplish brown olive that is grown in southern France. They are chewy and flavourful and like the Gaeta difficult to pit.
Sicilian green - These oversized green olives have a dense, somewhat tart flesh.