Cilantro / Coriander
Originating in Western Asia and/or Southern Europe, coriander has been cultivated at least since the days of Tutankhamen, and gathered wild from deep into prehistory. It was brought to North America by the first English and Dutch settlers, and to Latin America and the Canary Islands Spanish and Portuguese invaders. It is one of the most important herbs and spices through India, Southeast Asia, China and Africa. All parts of the plant are edible.
Cilantro - [Coriander Leaf, Fresh Coriander, Chinese Parsley; Dhania sabz (India); Won Soy, Wonsoy (Philippine); Xiang cai, Heung choy (China); Ngo, Mui (Viet); Pak Chee (Thai); Pak hom pom (Laos); Coriandolo (Italy); Coriandrum sativum (Parsley family)]
This herb was once in very wide use all over Europe, but has been almost completely supplanted by parsley. In Western Europe, only traditional recipes in southern Portugal and Spain's Canary Islands still call for it. On the other hand, it is greatly used in most non-European cuisines worldwide, and in the Caucasus where Cilantro and Coriander seed are the chief herb and spice of Georgia.
Many long years ago, when I first starting cooking, I was using the 1000 Recipe Chinese Cookbook and was totally mystified by all the calls for "Chinese Parsley". No such thing was sold in Southern California. Now remember, the public Internet was still 30 years away, so you couldn't get all your questions answered in 12 seconds back then. Today, all the markets have Cilantro, and the ethnic markets have heaps and piles of it.
There is a strong "I hate Cilantro" movement on the Internet, but the condition is curable by exposure. A leader of one such Web based group, after extensive testing for hate articles, realized to her horror that she had come to rather like cilantro and had to resign her post. Her's is far from the only such story.
Buying & Storing: Ethnic markets and farmer's markets are the best sources because you can count on it being fresh. If needed, it can be refreshed by cutting off the bottom 1/2 inch or so of the stems and standing in a cup with an inch of cool water in it. Remove any substandard leaves and bag it loosely in plastic. Stored in the refrigerator it will last more than a week but should be replaced weekly because it slowly declines in flavor. Dried is completely worthless and frozen isn't much better.
Cooking: Cilantro is most often used raw as a salad
ingredient, garnish or component of a salsa. When cooked it should be
added at the very end of cooking as heat quickly degrades the flavor.
Coriander Seed - [Dahnia (India)]
These "seeds" are actually dried fruits containing seeds. While not now used in Europe to anywhere near the extent they were in Medieval times, coriander seeds are still used in pickling and sausage making. In India they are used in vast quantity for all manner of curries and spice mixtures, almost always with Cumin at a ratio of about 1 T Coriander to 1 t cumin. This combination was also popular in Imperial Rome, and is used in Africa and the Middle East.
Buying & Storing: Clearly the best place to buy is in an Indian market where you can buy any quantity you need very cheaply and can be sure it's fresh. Otherwise the ethnic section of most independent markets. Store tightly sealed in a glass jar in a cool place away from light and it'll last about a year. Don't buy it ground which turns quickly to sawdust - grind your own as needed. European coriander tends to be a bit smaller and darker than that from India. The photo specimens, from India, were typically 0.140 inch diameter (3.6 mm).
Cooking: In India and parts of Africa coriander seed is dry roasted before grinding and/or incorporated in a recipe. Since it's almost always accompanied by Cumin, I roast the cumin first as it's easier to tell by smell when the pan is hot enough. The seeds should become aromatic and darken only just slightly. Cool before grinding.
Health & Nutrition: Researchers have recently found
coriander oil to be a powerful anti-bacterial agent, useful for food
preservation and safety. It was found effective against almost all bacteria
While perfectly edible, cilantro roots seem to be used only in the cuisine of Thailand, and to a much lesser extent in a couple of Thailand's neighbors. Roots are used as a component of curry pastes and in some soups.
Buying & Storing: The only place you're going to get cilantro roots is at a farmer's market, and even then you may have to ask the grower to bring you some the next week. If you cut the stems off as you would for carrots, cilantro root can be stored loosely wrapped in plastic refrigerated with the carrots and turnips. They will last for about 3 weeks, and can also be frozen, bagged with water to prevent freezer burn.
Subst: In recipes that call for roots, if you can't get
them, use stems, but no leaves.
This is actually coriander seeds, extracted from the fruit husks and toasted. It's very tasty but is strictly an Indian specialty available only in Indian markets. It is a relatively new product, and named partly in hope of getting around export taxes on spices by calling it "Dal". The courts ruled otherwise.
It is used primarily as a mouth freshener after meals. If it was not
toasted as purchased it should be lightly toasted, but not enough to
significantly change its color. It is also used in Sambars and the like
in Southern India.