The Truth is in the Yam, or is it the Sweet Potato?

Dining with Duvall By Lynn Duvall

I’ve never been clear on the differences between a sweet potato and a yam.

I know the yam is a variety of sweet potato, that it’s orange inside and doesn’t have a sweet taste. My mom told me the two were interchangeable in recipes. That turns out to be poor advice. When I researched the topic, I discovered that I was woefully ignorant on the subject. Maybe you’d like to digest a few facts that are new to you, too?

Sweet potatoes are native to the Americas. The traditional sweet potato was white inside, although today, most American commercial varieties are orange. Columbus and his crew probably tasted sweet potatoes on the voyage he made to the Americas in 1492, along with tomatoes, chile and corn. All those foods were unknown in Europe at the time. We imagine that tomatoes are uniquely Italian, but tomatoes only became popular in Italian cooking after the seeds from the New World were planted in Italy. Corn and sweet potatoes did not receive a hearty welcome in Europe.

Yams are also orange, but they are imported from the Caribbean. They taste dry and starchy, rather than sweetly moist. I do not know why they tend to be less expensive; perhaps it is because the yam growing season runs nearly all year, twice as long as the sweet potato season.

The way to tell the difference between the two is by appearance. Sweet potatoes are short and smooth with blocky ends. The yam is a longer cylinder with rough skin. The sweet potato has twice the daily recommended allowance of Vitamin A. A three-and-half ounce serving is also rich in Vitamin C, with some calcium, thiamine and iron, low sodium and only 141 calories. Sweet potatoes have more fiber than oatmeal. A yam is less nutritious.

Sweet potatoes made their way to New Zealand in 1850. Maori tribes had cooked a related vine-grown root for centuries, but those potatoes were fingerlings. The American potato was given the old Maori name and are sold as Kumara. In New Zealand, breeders developed three different styles: red, yellow and gold. Each has a different taste. New Zealanders rate Kumara, hybrid American sweet potatoes, as the their tenth favorite vegetable.

When you buy sweet potatoes, look for firm, solid roots. They bruise easily and should not be stored in the refrigerator. Here’s a tip that is a true time saver: sweet potatoes freeze beautifully. Simply wash and scrub the skin. Trim off any woody part. Puncture with a fork. Pop them in the microwave wrapped in a damp paper towel. Nuke them on high until they are soft. (About five minutes for one potato or eight minutes to ten minutes for three potatoes). Let cool, peel off skin with your hands and package them in freezer storage bags. Potatoes can be refrigerated up to 10 days or freeze and defrost as needed.

To boil sweet potatoes: cover with water, bring to a boil and cook for 15 minutes. Prepare a large batch by lightly spraying with cooking oil and baking on a cookie sheet at 400 degrees for 30 to 50 minutes. Cool, peel and freeze. Boiling brings out the sweetness. Baking is easy for preparing a big freezer batch. Microwaving might change the texture slightly, but it is faster.

If you’d like to try sweet potatoes in a new way, you could celebrate the upcoming holiday with Columbus Day Soup. Make two batches at once and freeze the second batch as this soup improves with reheating.

You might mention to your children that while textbooks state that Columbus’ voyages proved the world is round, another man in Greece taught his students that the world was round 2,000 years before Columbus was born. Pythagoras was the first Western scholar to proclaim the earth was not a disc, but was a globe rotating on its axis every 24 hours. Others who rediscovered Pythagoras’ work made excellent calculations about the size of that globe 1,000 years before Columbus’ birth. Even after Columbus’ voyages proved the world to be round, that knowledge didn’t reach the common people for hundreds of years.

I used Columbus Day as an example to my children of how history can be revamped to suit the philosophies of different times and societies. I taught my children respect for their teachers and the information they learned at school. I also counseled them to keep an open mind, to do their own critical thinking, to be aware that a solid fact today might turn out to be fable tomorrow, not to be afraid of questioning, and to accept flux and change.

Yams may be be cheaper than sweet potatoes but they aren’t interchangeable, so even though my mom was usually spot on, she was wrong about yams. I hope my views on history will hold up better than my mom’s advice on yams.

Lynn Duvall welcomes questions or comments at boblynn@ix.netcom.com or in care of the Valley Sun, P.O. Box 38, La Cañada, CA 91012-0038.

Canola oil spray I 1 medium onion, chopped I 2 small cloves garlic, minced |

1/2 teaspoon fresh ginger, minced | 1 small Granny Smith apple, chopped |

4 cups fat-free, low-sodium chicken broth | 2 pounds peeled sweet potatoes cut into 1/2-inch pieces | 1 cup low-fat milk | 1 1/2 teaspoons curry powder |

Salt and freshly ground black pepper, to taste | Plain nonfat yogurt, for garnish |

2 tablespoons finely minced fresh chives, for garnish

Lightly coat the bottom of a large saucepan with oil spray and heat over medium high heat. Add onion, garlic, ginger and apple and sauté until onion is translucent and apple is limp and fragrant. Add broth and bring to a boil. Stir in sweet potatoes and curry powder. Lower heat, cover and simmer until potatoes are very tender, about 20 minutes. Turn off heat under the pan.

With a slotted spoon, transfer sweet potatoes and other solids in the pan to a blender or food processor. Add a little of the liquid in the pan and purde until smooth. Add I cup of the liquid in the pan to the blender and mix at high speed until smooth. Stir the mixture into the remaining broth in the saucepan. Stir in the milk and heat until the soup comes to a simmer. Remove from heat and season with salt and pepper to taste.

Ladle soup into bowls and top each with a spoonful of yogurt. Garnish with a sprinkle of chives on top and serve immediately. This soup can be made a day ahead, refrigerated (covered) and rewarmed over medium heat. Makes 8 servings.

Per serving: 134 calories, less than 1 gram total fat ( 0 grams saturated fat), 29 grams carbohydrate, 5 grams protein, 5 grams dietary fiber, 345 milligrams sodium.