Here is the photo of what they were looking at:
As you can see, there are two kinds of sweet potatoes: one with dark pink skin (on the left) and one with blond skin (on the right).
So, what’s the difference?
It turns out that there are more than 6,500 different varieties of sweet potatoes around the world! The skin can range from dark red to light pink to blond to brown. The flesh can be dark orange to a pale yellow to almost white. There are even varieties that are purple inside and out! Sweet potatoes are produced in dozens of states, including North Carolina, Mississippi and California. But, all are from the same plant that belongs to the family Convolvulaceae. Click here to find out more about the different varieties.
Doug, my brother-in-law, is quite the sweet potato aficionado but has recently complained that his favorite variety, the Garnet Yam, is no longer grown commercially. He loves the sweet and creamy flavor and is frustrated that many farmers are growing varieties that are not as flavorful.
If you purchase sweet potatoes and are disappointed in the flavor, you’re probably on to something. Make a note of the variety, or ask your produce manager, so you know which sweet potatoes you prefer. You can also ask your produce manager the name of the grower and where they are grown!
If you think sweet potatoes are only for Thanksgiving, here is a recipe sent to me by my good friend Vicky. It’s from Mark Bittman's How to Cook Everything Vegetarian, and it's great year-round, especially for a summer potluck!
Roasted Sweet Potato Salad with Red Pepper Vinaigrette
Makes: 4 servings
Time: About 45 minutes
The red pepper dressing is tart, sweet, and spicy, with a touch of cumin. This is best served warm or at room temperature, though of course you can refrigerate and serve it up to a day later, as long as you take it out of the refrigerator beforehand to take the chill off.
4 large sweet potatoes
½ cup extra virgin olive oil
Salt and freshly ground black pepper
1/4 cup red wine vinegar or sherry vinegar
1 medium red bell pepper, cored, seeded, and ¬ quartered
2 teaspoons ground cumin
1 tablespoon grated orange zest (optional)
1/2 cup sliced scallion
1/2 cup minced fresh mint or parsley leaves
1 or 2 fresh minced chiles (jalapeño, Thai, serrano, or habanero), or to taste
1/4 cup raisins (optional)
1. Preheat the oven to 400˚F. Peel the sweet potatoes and cut them into bite-sized pieces. Put them on a baking sheet, drizzle with 2 tablespoons of the oil, and toss to coat. Sprinkle with salt and pepper and roast, turning occasionally, until crisp and brown outside and just tender inside, about 30 minutes. Remove and keep on the pan until ready to dress.
2. Make the dressing while the potatoes cook. Put the remaining 6 tablespoons oil in a blender, along with the vinegar, bell pepper, cumin, and zest if you’re using it. Sprinkle with a little salt and pepper. Purée until smooth.
3. Toss the warm potatoes with the scallion, mint, chiles, and raisins if you’re using them. Add 1/2 cup of the dressing and toss to coat, adding more if necessary. Taste and adjust the seasoning. Serve immediately or at room temperature.
Source: Mark Bittman; How to Cook Everything Vegetarian
P.S. Did you know that sweet potatoes are technically not "yams"? Read my previous post about this.