^ minimum 10 tonnes
Generally, olives that are to be pickled green are harvested when the fruit has reached a yellow-green colour. Pick a sample olive and cut it through to the pit. Continue the cut around the diameter of the olive until you can remove one half of the olive, leaving the pit embedded in the other half. You should be able to easily free the pit from the flesh with your fingers. Another guide to determine whether the fruit is ready for harvesting is to simply squeeze a yellow-green olive with your fingers. If the juice is a milky white rather than clear, then the olive is ready for picking.
Fruit is pickled as ‘naturally black’ olives must be completely ripe (but not over ripe). Cut through a black/purple olive and observe the flesh colour. If the dark colour penetrates the flesh to within 2mm of the pit (on a medium size olive), then the olive is ripe. If the flesh has become completely dark, that is, right to the pit, then many would consider that the olive is over ripe whilst others find that this suits their processing methods.
When olives are transformed into edible table olives, they are rendered less bitter by soaking in water or brine solution. The final flavour of the olive depends on the variety, fermentation, processing solution and the final soaking solution. That is, salt, vinegar, marinades, herbs and spices.
For new table olive producers, processing the green or black olives in 10% brine (salt) is the simplest method. In fact olives, particularly green olives, can be in 10% brine for one to two years so that marinating or stuffing can be carried out later as required.
Naturally black ripe olives, are processed mainly by soaking in brine, dehydrating in the sun or oven, dry salting or allowing them to shrivel on the tree. A simple method of presenting table olives is packing them in olive oil. For example, naturally black ripe Leccino olives can be packed in Leccino olive oil. Here the olives can be either be eaten on their own, the olives and oil poured over salads or the oil used separately. If these olives are unsalted, they can be eaten by persons on restricted salt diets.
When naturally black-ripe olives are processed in brine they can lose their intense purple colour resulting in olives ranging from pale to dark brown in colour. This is a particular problem with black Verdale olives.
Some processing methods involve a step where air is passed through the processing vessels containing the olives and soaking solution, inducing the olives to turn pitch black in colour.
Here the polyphenol compounds in the flesh darken when they chemically react with the oxygen in the air. A similar effect can be obtained by allowing processed olives to stand in an uncovered vessel overnight.
The size of the olive is a function of the variety, but can change from year to year because of the growing environment and crop load. Table olives are either thinned out to produce larger olives or they are sorted into a different size grades before or after processing.
Larger sizes fetch higher prices although medium sized olives are better for adding to salads. Following the basic transformation, olives of any style can be marinated, de-pitted, sliced or stuffed or turned into tapenade.