Real Food Encyclopedia | Sweet Potatoes

Aside from sweet potato fries, we bet that most people eat sweet potatoes primarily at Thanksgiving. It seems like people fall into one of two factions for the big meal: those who like marshmallows with their sweet potatoes, and those who find the sweet-on-sweet combination revolting. In fact, despite its reputation as a holiday for “togetherness,” Thanksgiving seems to inspire much food-related conflict: should stuffing have fruit in it? Is green bean casserole yummy, or repellant? Is deep-frying a turkey awesome, or deeply terrifying?

One thing we can all agree on: the necessity of sweet potatoes on our tables, marshmallows or not.

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Fun Facts about Sweet Potatoes:

  • In folk medicine, sweet potatoes have been used as a natural treatment against intestinal parasites. There may be some truth to this, as there is some evidence that the Vitamin A (beta-carotene) found in sweet potatoes provides some protection against certain gut-affecting parasites.
  • George Washington Carver, the remarkable resuscitator of southern agriculture and champion of the sweet potato and peanut, created a list of over 100 different sweet potato-based products from his scientific research, including glue, dye and something called “mock coconut.”

What to Look for When Buying Sweet Potatoes

Sweet potatoes come in a rainbow of colors, shapes and sizes. Most sweet potatoes are large and football shaped, with a fat middle and tapering ends, although some heirloom and indigenous varieties are quite small and slender (like the taputini, a traditional Maori cultivar).

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, creamy white (like the Japanese sweet potato) or even purple-magenta (as seen in the stunning Okinawan sweet potato). 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

Sweet potatoes are number 31 on the Environmental Working Group’s Shopper’s Guide to Pesticides in Produce. The roots are susceptible to several different pests and diseases that are controlled with insecticides and fungicides, so check with your local sweet potato farmer if you’re concerned about this.

Sweet Potatoes Seasonality

In the United States, sweet potatoes are generally harvested in September and early October. However, it can take up to eight weeks of curing and storage after harvest before sweet potatoes sweeten and develop the texture we are accustomed to, putting the root’s peak seasonality at … right around Thanksgiving. Sweet potatoes will be in season in most parts of the US through very early spring.

Sweet Potatoes and Geography

Sweet potatoes grow better in warmer climates. China by far leads the world in sweet potato production, followed by Uganda, Nigeria and Indonesia. North Carolina leads the US in sweet potato growing, followed by California, Mississippi and Louisiana.

The origin of the sweet potato is thought to be somewhere between southern Mexico and Venezuela, but current research narrows the field to Central America. It was probably domesticated in Peru between 4,000 and 5,000 years ago. Columbus took the plant home with him when he returned to Europe in the late 15th century, and from there Spanish and Portuguese explorers dispersed it to the rest of the world.

The exception to this is Polynesia: sweet potatoes were already being cultivated by the 13th century (long before European contact) on several far-flung Polynesian islands, and became an important staple food on some. How did sweet potatoes get there, you ask? A ho-hum “non-human mediated dispersal” (i.e., birds carried the seeds over) theory is a contender, but a way more interesting theory is that ancient Peruvian sailors, either blown off course or through deliberate navigation, brought the plant to Polynesia. This theory is supported by the fact that the names for sweet potato in several Polynesian languages are suspiciously like the Quechua (a native Andean language) word for the plant.

An important clarification: Sweet potatoes are not yams, and vice-versa. They are two totally unrelated botanical species, although the roots can be similar in shape. What’s the difference? The true sweet potato (Ipomoea batatas) is a vine related to the morning glory (both in the Convolvulacea family) and is native to South America; the yam is from the Dioscorea family, native to Africa and Asia. All of this is especially confusing because orange-fleshed sweet potatoes have been traditionally referred to as “yams” in parts of the US. In general, true yams have a drier texture, are starchier in taste, and are much lower in beta-carotene (but higher in protein) than sweet potatoes.

Eating Sweet Potatoes

Storing Sweet Potatoes

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 with Sweet Potatoes

Sweet potatoes can be the star of just about any part of the meal, from side dish to main course to dessert. The root can be baked, roasted, boiled, fried, grilled, mashed or pureed. (Also, check out this technique for a quick microwaved sweet potato, so you can get your sweet potato fix even at the office.)

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 oranges (juice or zest) and apples. 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 for those of you firmly entrenched in the sweet potatoes-with-marshmallows camp, check out these sweet potato biscuits with marshmallows.) Some even prefer sweet potato pie to pumpkin. Is that Thanksgiving blasphemy?

And get to know the savory (rather than sweet) side of sweet potatoes, especially in these combinations: sweet potatoes and rosemary; sweet potatoes and chipotle chiles; and sweet potatoes and cumin.

Sweet potato leaves and young shoots are also eaten as part of the cuisines of a number of cultures, including Chinese, Polynesian and Filipino. (Here’s a great recipe roundup for sweet potato leaves.)

Pro Tip: Cook sweet potatoes in their skin to retain the most nutrients (you can peel after cooking).

Preserving Sweet Potatoes

Cooked sweet potatoes can be frozen (as slices, whole or pureed). They can also be canned.

Sweet Potato Nutrition

Sweet potatoes are good for you, especially varieties with orange or purple flesh. They contain truly awesome amounts of Vitamin A — between 500 percent and 700 percent of your recommended daily intake in just one cup. (Vitamin A is a vitamin necessary for eye, immune system and skin health, and is also a powerful antioxidant.) Sweet potatoes also contain fiber, excellent amounts of Vitamins C and B-6, manganese, potassium and several other vitamins and minerals. They are even good sources of iron and calcium. Sweet potatoes are also thought to be helpful in blood sugar regulation.