The Mighty Sweet Potato

I have always had, and probably always will have, a great love for a particular type of tuber: the sweet potato. This root crop fights for the top spot on my list of favorite foods with strawberries and rainbow Swiss chard. Before I get deep into the numerous attributes of this fantastic vegetable, however, let’s clear one thing up: the sweet potato versus the yam.

Elazar Sontag, writing about sweet potatoes in Serious Eats, notes that they are not actually potatoes, which are members of the Solanum tuberosum family. Instead, they are, like morning glories, Convolvulaceae. In the early 1900s, Southern farmers started using the term “yam” to refer to a new variety of sweet potato they were growing. It had orange flesh, and Americans knew only white-fleshed sweet potatoes at that time.

A yam is something else altogether. If you have read Chinua Achebe’s Things Fall Apart, then you are already familiar with the yam — “the king of crops,” as Achebe describes it. Yams, which are in the Dioscoreaceaeare family, are native to Asia and Africa, whereas sweet potatoes are native to Central and South America. They are starchy, like sweet potatoes, but the flesh is white, the skin is very rough and brown, and the taste is more akin to a regular potato than a sweet potato.

Grocery stores around here don’t stock real yams, but I have seen orange-fleshed sweet potatoes labeled “yams” many times.

It turns out that my own love for sweet potatoes is only the most recent in a long chain of human adoration of this tuber. According to an article by Jennifer Harbster on the website of the Library of Congress, archaeologists have found evidence to suggest that sweet potato cultivation started in Peru as early as 2500 BCE.

Then there’s the question of nutrition. A few years ago, I was looking at a copy of The Blue Zones Kitchen, a cookbook by Dan Buettner that features areas of the world where people are the longest-living. One such place is Okinawa, Japan where, before modern processed foods reached them, two-thirds of the average diet was a type of purple sweet potato called beni imo. All sweet potatoes are high in vitamin A, vitamin C, manganese, vitamin B6, and a host of other good-for-you things, but the purple ones have the added benefit of anthocyanins — the same lovely antioxidants present in blueberries that reduce inflammation and fight disease. No wonder people in Okinawa were living so long.

If I’m 100-percent honest, neither the long history nor the numerous health benefits is my reason for consuming so many sweet potatoes. My number-one reason is enjoyment. When I was a child, sweet potatoes were on my birthday dinner wish list. Once I was old enough to cook and shop for groceries, I made an excellent discovery: sweet potatoes come in all different colors and varieties.

Among the small but interesting display of vegetables at the back of my local market, the Orleans Whole Food Store, I’ve found white-fleshed Japanese sweet potatoes, red garnets, orange Covingtons, Stoke’s purple, and Ben Yagi with mottled purple-and-white insides. (Those living at the outermost end of the Cape will be glad to know that I’ve sometimes found the purple and white varieties at Stop & Shop, and that the purple ones appear often at the East End Market in Provincetown and at Salty Market in Truro.)

I’ve tried them all. The white-fleshed Japanese are extra dense and starchy. I steamed them with the red garnets and mashed them together with butter and salt for a light-orange delicacy. The Ben Yagi didn’t need anything except steaming and a little sea salt. The orange Covingtons were perfect for halving and roasting or for adding to stews. The Stoke’s purple, I found, was my favorite. I had never seen a food that deep in color — royal purple, I might call it. Slicing into them never gets old for me; these really satisfy my sideline quest to discover the most fabulously colored foods.

After all this sweet potato love, you’re probably thinking, “Where’s the recipe?” I am a bit of a purist when it comes to sweet potatoes and will happily eat them plain. That said, orange-fleshed sweet potatoes are delicious paired with a nutty tahini sauce and sprinkled with a few chives or scallions. The extra-sweet purple varieties benefit from some tangy lemon and miso, and when you want nothing but comfort, the combination of white and orange simply mashed with some butter and salt is just the thing. In all cases except for mashing, I leave the skins on (so many good nutrients in those skins!), but feel free to peel or not as you please.

ORANGE-FLESHED SWEETS WITH TAHINI SAUCE
Makes 2 servings

2 orange-fleshed sweet potatoes
¼ cup tahini
¼ cup water
2 Tbsp. lemon juice
1 Tbsp. olive oil
¼ tsp. ground cumin
¼ tsp. ground coriander
¼ tsp. salt

Chives or scallions for garnish (optional)

1. Scrub sweet potatoes and slice them in half lengthwise. Place cut side down on a baking sheet lined with parchment paper.
2. Roast at 400° F degrees for 20 to 30 minutes until soft.
3. While the potatoes are roasting, whisk together the rest of the ingredients for the tahini sauce in a small bowl.
4. Turn warm sweet potato halves onto a plate, drizzle with tahini sauce, and garnish with a sprinkle of chopped chives or scallions.

PURPLE SWEETS WITH MISO AND LEMON
Makes 2 servings

2 lbs. purple sweet potatoes
2 Tbsp. melted ghee (or butter)
2 Tbsp. fresh lemon juice
2 Tbsp. miso (white miso will be lighter and sweeter, red will be more assertive)
Sesame seeds for garnish (optional)

1. Scrub your sweet potatoes and chop into one-inch cubes.
2. Place in a steamer basket over boiling water and steam for 10 minutes or until they’re fork tender.
3. While the potatoes are steaming, whisk together the ghee or butter, lemon juice, and miso.
4. Once the potatoes are done, turn them out into a bowl and drizzle the miso-lemon mixture on top. Stir gently to distribute and sprinkle with sesame seeds if using. Serve warm.

BI-COLOR MASHED SWEETS
Makes 2 servings

2 medium orange-fleshed sweet potatoes
1 medium white-fleshed sweet potato
1 Tbsp. ghee (or butter)
Salt to taste

1. Rinse your sweet potatoes, peel, and cut into 1-inch cubes.
2. Place in a steamer basket over boiling water and steam for 10 minutes or until they’re fork tender. White sweet potatoes (especially the Japanese variety) may take longer to cook. It’s OK if the orange ones get extra soft.
3. Empty the water from your steamer pot and pour the potatoes back in. Add ghee or butter and salt to taste. Stir to evenly distribute.
4. Remove the pot from the heat and mash with a fork or masher until mostly smooth with a few small chunks remaining.
5. Serve warm and feel happy.