Few flavors are as controversial as cilantro, the strong tasting herb that once even inspired a website dubbed "I Hate Cilantro." Julia Child named it as one of the few foods she refused to eat, even going so far as to say she would pick it out and throw it on the floor if she found it in her meal. Researchers have identified a gene linked to cilantro aversion, one that supposedly makes the leaves taste like soap or metal. But not everyone who hates cilantro is born with that gene, and not everyone born with that gene hates cilantro. Coriander, the dried seed of the same plant, has a strong flavor as well, though it doesn't usually inspire nearly as strong a reaction.
Nuances of Flavor
Like most herbs, fresh cilantro has a bright, intense flavor. Whether you love it or hate it, it hits high notes on your palate and is mostly served raw rather than cooked because cooking mellows its flavor, making it less distinctive. Coriander, or cilantro seed, is usually used dried and ground. Its flavor is deeper and, while some eaters have a strong dislike for it as well, it doesn't inspire nearly the same outrage as the fresh leaf. Cilantro leaves actually don't taste much like dried coriander seeds. However, when the plant first starts to go to seed, before the seeds are picked and dried, its flavor calls to mind both ground coriander spice and fresh cilantro leaves.
Both coriander and cilantro are used in a variety of Asian foods, although they are mostly used differently. In Indian food, cilantro tends to be used as a garnish that adds a bright finishing note. In contrast, ground coriander seed is cooked with a blend of other spices, adding a sweet and astringent element to curry powder mixtures. The same is true in Thai food: ground coriander seed is a component in curry pastes, while cilantro leaf is used raw in salads, fresh spring rolls and garnishes. Similarly, in Mexican food, coriander seed is used in soups and stews while cilantro is common in fresh salsas.
A Question of Balance
Unless your aversion to cilantro is so strong that you won't even taste anything that's touched it, you may find that a mild dislike for its flavor can be mitigated if it is used judiciously and kept in balance with other flavors. Use enough for its flavor to contribute to the overall seasoning of a dish, but not so much that it overpowers the other ingredients. Similarly, use ground coriander as one spice among others, and don't use enough to overpower other elements, unless a recipe specifically calls for a disproportionate amount.
What's in a Name?
Although cilantro leaf and coriander seed are clearly different animals, Americans may be the only ones to distinguish between them so clearly. In other parts of the world, cilantro is often called "fresh coriander" or "coriander leaves." Although the herb and the leaf have different names in American cookbooks, these names are actually closely related. "Cilantro" comes from the Spanish word for coriander.