Real Food Encyclopedia | Sweet Potato
Let’s get this out of the way: Sweet potatoes are not yams. Though yams are similar in shape (and though their name is used regularly, in the U.S., to describe all manner of sweet, orange side dishes) these two are, botanically, mostly unrelated. While production of the true yam is concentrated in Africa, the sweet potato, Ipomoea batatas, is native to the Americas — the root of a vine related to the morning glory.
We bet that most people have sweet potatoes on their table at Thanksgiving. It seems like there are two factions: Those who like marshmallows on top, and those who find the sweet-on-sweet combination revolting. One thing we can all agree on — the necessity of sweet potatoes, marshmallows or not.
Fun facts about sweet potatoes:
- George Washington Carver, the remarkable resuscitator of Southern agriculture and champion of the peanut, also promoted the cultivation of sweet potatoes. Carver created a list of over 100 different sweet potato-based products from his scientific research, including ink, dye, many types of adhesives and three types of after-dinner mints.
- In Polynesia, there is evidence of sweet potatoes dating to around 1000 CE — long before the plant was assumed to have left the Americas. This may indicate that Polynesian and Native American peoples were in contact far earlier than previously believed, a theory supported by the fact that the words for sweet potato in several Polynesian languages sound suspiciously like Quechua. (Other theories include “non-human mediated dispersal,” e.g. seeds carried by birds.)
What to look for when buying sweet potatoes
Sweet potatoes come in a rainbow of colors, shapes and sizes. Their skin can be russet, tan, cream, light purple or red. Sweet potato flesh is just as colorful: It may be orange (like the common Jewel sweet potato), yellow or creamy white (like the Japanese sweet potato) or even purple (as seen in the stunning Okinawan sweet potato).
Most sweet potatoes are large and football-shaped, with a fat middle and tapering ends — though some heirloom and indigenous varieties are quite small and slender, such as the Taputini, a Maori cultivar.
Sweet potato varieties are also divided into “dry” varieties (better for frying or boiling, because they hold their shape better) and “moist” or “baking” types.
Sustainability of sweet potatoes
Pesticides
Sweet potato roots are susceptible to several different pests and diseases that are controlled with insecticides and fungicides. Still, they make the “Clean 15” in the Environmental Working Group’s 2023 Shopper’s Guide to Pesticides in Produce, ranking No. 34 out of 46 produce varieties tested for pesticide residue. Those who want to cut down on potential pesticides should buy organic or check with their local farmer about their growing practices.
Seasonality
In the U.S., sweet potatoes are generally harvested in September and early October. However, it can take up to eight weeks of “curing” after harvest before they sweeten and develop the texture we are accustomed to, putting the root’s peak season at — perfect timing — right around Thanksgiving. In most parts of the country, the season will extend through very early spring.
Geography
Sweet potatoes grow best in warmer climates. North Carolina leads the U.S. in sweet potato growing, with California and Mississippi also contributing. 2022 data from the U.N.’s FAOSTAT indicates that China, by far, leads the world in sweet potato production, followed by Malawi, Tanzania, Nigeria and several other African nations.
Sweet potatoes, which originated in Central or South America, were first cultivated in Peru, perhaps as early as 2500 BCE. Columbus took the plant home with him in the late 15th century, after which it spread around the world. The exception to this timeline, as we mentioned earlier, is Polynesia.
Eating sweet potatoes
Storing
Sweet potatoes can be stored for several weeks under the right conditions: cool, dry and away from light. Don’t store them in the refrigerator, as this accelerates their decline; they don’t like to be too cold or too moist. Sweet potatoes that get too warm tend to sprout and become shriveled and mushy.
Cooking
Sweet potatoes are commonly paired with cinnamon, nutmeg, ginger and other warming spices, along with brown sugar or maple syrup. They also are delicious paired with orange and apple. They can be mashed and added to any number of baked goods, like muffins, biscuits and cakes. (Sweet potato bourbon Bundt cake? Yes please.) And of course, we can’t forget sweet potato pie.
But sweet potatoes can be the star of just about any part of the meal. The root can be baked, roasted, fried, grilled, mashed or pureed. (To get your sweet potato fix at the office, you can even microwave them.) Get to know their savory side by pairing them with rosemary, cumin or chipotle, all excellent combinations. Cook whole sweet potatoes in their skin to retain the most nutrients and moisture — you can always remove it later, if necessary.
Sweet potato leaves and young shoots are also edible and are common in many cuisines, including Chinese, Vietnamese and Filipino.
Preserving
Sweet potatoes make for unusual pickles and preserves. Cooked sweet potatoes (sliced, whole, or pureed) can be frozen or canned.
Nutrition
Sweet potatoes are good for you, especially varieties with orange or purple flesh. They contain truly awesome amounts of Vitamin A — one large sweet potato, baked in its skin, contains almost twice your recommended daily intake, plus six grams of fiber. Sweet potatoes also contain excellent amounts of Vitamins C and B6, manganese and several other vitamins and minerals.
In folk medicine, sweet potatoes are sometimes used as a treatment against intestinal parasites. There may be some truth to this, as there is some evidence that Vitamin A provides some protection against certain gastrointestinal parasites.
Top photo by richardcoombs58/Twenty20.