The style of olive is determined by the method of processing. The unique black color of the California ripe olive is produced by oxidation, a flow of air is released into the tank of olives. The mellow flavor is a result of neutralizing the natural bitterness of the fruit and leaching them to a neutral pH. Ripe olives are pressure canned in a brine solution. They are available in cans as whole, pitted, halved, sliced and chopped. Green ripe olives are not exposed to air.
Green olives are the most popular for home food preserver.
The ABC's of Home-Cured Green Ripe Olives, leaflet 21131, is available from your local Cooperative Extension office. Using this procedure, green olives should be kept in the refrigerator and used within 2 to 4 months. Before eating, soak olives overnight in fresh water to remove excess salt. Use within 3 days after soaking. Home canners should be aware that olives are a low-acid food and require careful handling to prevent botulism.