There are three basic types of olives–green, violet and black–which reflect their stage of ripeness as all of them start green. Use green or violet olives for tagines and if you find them too salty, soak them in water for up to an hour before cooking.
It is said that olives have a slightly salty, bitter taste that makes you cry but a bland olive tastes of nothing. Supermarkets now have olive bars, so some of this has been relieved by demand from the public for violte-black, brownish and green olives. Black olives are nearly always devoid of taste, unless salt cured for ages, and devoid of taste. Remember that all olives are green when picked, this should give you some hint as to the flavor. Although you cannot eat an olive fresh from the tree–but, you can, and I encourage you to do so, just for the reminder that they are inedible. They all go through a salt curing process and they range in varities from the:
- small, black and delicate, Taggiasca
- those on terraces and silver trees, cured by soaking for 40 days in salt water, changed daily scented with thyme, rosemary and bay
- those in brine, never ready marinated, but often refreshed with a mix of olive oil, chiles, and garlic
- unpitted and uncured
- the American variety, often canned, pitted, pasteurized, and pitted, and others to be avoided
The best olives cost a little more because they are freshly imported (think what would happen to peaches, if you are an American just getting acclimated to real olives), and they are best pitted at the last-minute, and better yet, cured at the last-minute if you can find them uncured and fresh. They are a world away from their canned cousins. Sterilized jars, 2 lbs. of fresh olives, 1 c. sea salt, and stored tightly for 12-14 days with turning daily in the refrigerator and you will have what the French, Italians and Spaniards have on a daily basis. There is no going back.