UW Extension

Did you know a sweet potato is not a yam? When it comes to the yam, there is a bit of confusion. What you’ve been referring to as a “yam” is most likely a sweet potato. You may have never even tasted a yam.

The so-called “yams” in the supermarket produce section are nearly always sweet potatoes. Some people think that red-skinned, long sweet potatoes are yams, but they surely are just one of many varieties of sweet potatoes.

Sweet Potatoes vs. Yams

“Sweet potato” and “yam” are often synonyms in recipes and at the market. They are two different plants and even belong to different plant families. Here’s how to tell them apart.

Sweet Potatoes

Sweet potatoes are a member of the Morning Glory family. Sweet potatoes are native to Central and South America. In the U.S., North Carolina is the number one sweet potato-producing state.

Sweet potatoes are harvested in the fall but can be purchased year-round. Fresh sweet potatoes are found in the produce section and pre-peeled and cooked varieties of sweet potatoes in purée or frozen forms.

Sweet potatoes are generally more slender in appearance than russet potatoes and have tapered ends. Yam are not as sweet as sweet potatoes in taste.

There are four main flesh and skin color combinations of sweet potatoes available in America. Sweet potato flesh can vary from purple to white or orange depending on the variety.

The Covington is a favorite for mashing or roasting. It has rose-colored skin and sweet orange flesh.

A sweet potato that is white has a pale copper skin. Its white flesh is sweet, creamy and ideal for soups and stews.

Oriental sweet potatoes have red skin and dry, white flesh. Try them roasted.

Purple sweet potatoes have both purple flesh and purple skin. Their nutty flavor lends well to baking and roasting.

Sweet potato recipes range from savory to sweet. While you may usually top sweet potatoes with brown sugar and marshmallows at Thanksgiving, there are healthier ways to prepare them. They can be baked, boiled, fried, grilled, microwaved, pureed, roasted or steamed.

Yams

True yams are relatives of lilies. They are starchy edible roots. They are less sweet, often larger and always starchier than sweet potatoes.

Yams are shaped more like logs than tapered sweet potatoes, and they have thick skin that’s either smooth, tufted with hairs or streaked.

For culinary purposes, yams are almost always cooked since they may contain toxins that can only be destroyed by heat. Cooked yams are mildly flavored, slightly sweet and nutty. Yam texture ranges from soft and crumbly to fibrous and waxy.

Nutrition

Sweet potatoes have more sugar, protein, calcium, iron, sodium, vitamin A, beta-carotene and water than yams. One cup of raw sweet potatoes is about 114 calories, according to the USDA. They are a good source of fiber with complex carbohydrates and vitamins A and C. Nutritional value increases when you eat the sweet potato skin.

Selection

Choose sweet potatoes with no blemishes, firm skin, smooth or bruises. Medium and small-sized sweet potatoes taste better than large fibrous ones. Avoid sweet potatoes that are sticky, damp, withered, wrinkled or sprouting.

Storage

Sweet potatoes can be kept for up to two weeks in a dry, dark, cool, dry and well-ventilated place. Avoid storing sweet potatoes in the refrigerator, producing a hard center and unpleasant taste. If stored properly, sweet potatoes will last for up to two weeks.

Cooked sweet potatoes can be stored for 3-5 days in the fridge in an airtight container. Sweet potatoes should be blanched, partially or fully cooked before freezing.

Cooking

Handle sweet potatoes carefully to prevent bruising. Wash and cut off any brown spots before using. Sweet potatoes can be cut into cubes, matchsticks, rounds, wedges or other shapes.

To cut larger sweet potatoes, apply your weight to thrust a knife through them. Rinse the flesh to avoid browning.

Not sure how to cook sweet potatoes? Sweet potato soups, casseroles and fries are a few of the most popular ways to prepare sweet potatoes, but many other options are available. An excellent addition to the meal is roasted sweet potatoes, too.

Flavorings

Sweet potatoes have a sweet-spicy flavor and when paired with savory dishes that need some sweetness, such as turkey or pork, they are excellent.

Sweet potatoes go well with brown sugar, bourbon, butter, ginger, honey, orange, pecans, rum, rosemary and spices.

Break out of your food rut with the help of sweet potatoes! Sweet potatoes are a nutritious and delicious vegetable with easy ways to enjoy them. This vegetable is a colorful and healthy addition to every plate.

(Sources: fdc.nal.usda.gov; fruitsandveggies.org; ncsweetpotatoes.com; http://www.usda.gov/)