Other Names: Yam.
General Description: Sweet potatoes (Ipomoea batatas) are sweet-fleshed, pointy-ended tubers in the Convolvulaceae family. Native to the New World, sweet potatoes traveled to the Old World before the potato. Columbus introduced them to Europe with the name batata, later potato. When the tuber we now call potato came on the scene, it was given the same name, and the sweet varieties began to be distinguished from them, rather than vice versa. The sweet potato is botanically unrelated to the potato or the African yam. The word “yam” is an English adaptation of nyami, the Senegalese word for the large starchy African tuber from the Dioscorea family. African yams are rather bland and dry, so they’re often served with spicy sauces. They are imported to the U.S. from the Caribbean.
In the 1930s, Louisiana farmers chose the word “yam” to set their product apart from the dry, pale sweet potato grown in the North. In American markets today, “yams” are sweet potatoes with vivid orange color, and, when cooked, are sweet and moist. The most popular yam is the Beauregard, which is uniform in size and shape with smooth skin and deep orange flesh. Other varieties include Garnets, which have garnet-colored skin, orange yellow flesh, and excellent flavor. They are popular with organic growers. Jewels have more orangey skin and deep orange flesh.
Dry-fleshed yellow or white sweet potatoes are grown in the northern part of the U.S. These have pale white-to yellow flesh and beige skin. They appear occasionally at local markets with names such as Nancy Hall and Jersey Yellow sweet potato.
Boniatos are starchy reddish-skinned sweet potatoes whose white flesh is dry and fluffy with delicate, mildly sweet flavor similar to chestnuts. Boniatos are popular in Latin American and Asian markets and are a staple in countries from Mexico to Vietnam. There is a Hawaiian sweet potato called Okinawa—poni in Hawaiian—that cooks to a lilac color and has rich, sweet flesh.
Asian sweet potatoes are various rose-skinned, ivory-fleshed cultivars. They fall between the drier boniato types and the moist-flesh whites. More than 90 percent of the world’s sweet potatoes are grown in Asia.
Season: Year-round, with the greatest selection in the winter.
Purchase: Choose firm sweet potatoes with smooth, unbruised skins without cracks.
Avoid: Do not buy wrinkled, sticky, or sprouting sweet potatoes.
Storage: Because of their high sugar content, sweet potatoes don’t keep very well, so store them in a cool, dark place—but not the refrigerator—and don’t plan to keep them more than 1 or 2 weeks.
Note: Sweet potatoes may be peeled before or after they are cooked.
If peeling before cooking, use a vegetable peeler or sharp knife to remove the skin and discard. If peeling after cooking, cut the sweet potato open and scoop out the flesh.
Serving Suggestions: Bake whole sweet potatoes in their skins and serve with butter. Make a sweet potato pie by baking or steaming orange-fleshed yams, then beating the mashed flesh together with brown sugar, egg, and cream and baking in a pastry shell. Mash boiled sweet potatoes and potatoes together (for extra smoothness), adding grated fresh ginger and a little ground cardamom. Fry boniato sticks like French fries.
Flavor Affinities: Bourbon, brown sugar, butter, ginger, honey, orange, pecans, rosemary, rum, spices.
from Quirk Books: www.quirkbooks.com