Olives are the fruits of the plant of the same name, and differ from each other essentially by their colour, which varies depending on the level of ripeness reached between yellow, in the early stages, green and, finally, black. Green olives, in this regard, are particularly characterized by their relatively high sodium content, to which is also added the presence of a modest quantity of vitamins: this type of olives often finds space in aperitifs, or again, they are ideal for preparing excellent and tasty focaccias, and before they can be consumed, they must be treated in brine to reduce the degree of bitterness given by the polyphenols.