The most commonly used methods are these two:
This well-known process, starts with the immersion of the olives in a diluted lye solution to remove the bitterness, before naturally fermenting with salty water. After some time they will be ready for consumption and conservation.
This more recent process allows the green olives to mature more quickly by immersing them in brine and adding air (oxygen). In this way, green olives are transformed into black olives.
Other traditional methods used in Seville to treat olives are:
Cured in brine
The olives are fermented naturally using only water and salt before being ready for consumption. This is perhaps the oldest of all the methods.
In order to dehydrate olives and turn them into pasas or prietas (traditional names), the olives are laid out to dry, covered with salt and pressed to remove the water along with the bitterness.