Even though more attention has been sometimes been given to their delicious oil than their whole food delights, olives are one of the world's most widely enjoyed foods. Technically classified as fruits of the Olea europea tree (an amazing tree that typically lives for hundreds of years) we commonly think about olives not as fruit but as a zesty vegetable that can be added are harvested in September but available year round to make a zesty additionto salads, meat and poultry dishes and, of course, pizza.
While some olives can be eaten right off of the tree, most olives sold commercially have been processed to reduce their intrinsic bitterness. Processing methods vary with the olive variety, region where they are cultivated, and the desired taste, texture and color. Some olives are picked unripe, while others are allowed to fully ripen on the tree. The color of an olive is not necessarily related to its state of maturity. Many olives start off green and turn black when fully ripe. However, some olives start off green and remain green when fully ripe, while others start of black and remain black. In the United States, where most olives come from California, olives are typically green in color, picked in an unripe state, lye-cured, and then exposed to air as a way of triggering oxidation and conversion to a black outer color. Water curing, brine curing, and lye curing are the most common treatment processes for olives, and each of these treatments can affect the color and composition of the olives.