For most of us, yams and sweet potatoes are easily confused. Are they the same? Are they different? We’re here to set the record straight: sweet potatoes are not a type of yam, and yams are not a type of sweet potato. They are both root vegetables that come from a flowering plant, but they are not related.
A yam is a starchy root of the Dioscorea genus that is native to Africa and Asia. They are cylindrical in shape and have rough brownish bark-like skin. The flesh is white, purple or reddish. Compared to sweet potatoes, yams are lower in beta carotene, starchier, and drier. Compared to sweet potatoes, yams taste less sweet. True yams can be difficult to find in the United States and are more likely to be sold in international or ethnic food stores.
The sweet potato is part of the morning glory family. There are several varieties and the flesh and skin ranges in color from white to yellow to orange to purple. They have an elongated shape with tapered ends. The varieties can be grouped together into two major types; (1) firm, which have golden skin and paler flesh or (2) soft, which have copper skin and orange flesh. The firm variety was the first to be produced in the U.S., so when “soft” sweet potatoes began to be produced commercially, there was a need to differentiate it from its firm counterpart. Since the “soft” sweet potatoes slightly resemble true yams, the name was picked up and became what you see commonly labeled as “yams” in grocery stores.
In summary, know what kind of sweet potato you want for your recipe, and be alert to the yam/sweet potato labeling concept. More importantly, don’t be afraid to examine the vegetables, look at the color of the skin and the flesh and ask questions!
Here’s a summary of the most common sweet potato varieties available this season:
Garnet Sweet Potato
Garnets have dusty brown maroon colored skin which happens to be the inspiration behind its name. Inside, the flesh is a brilliant golden orange. It is starchier and moister than other varieties and offers mild sweet flavor with savory earthiness. These are great for baking, casseroles and mashing.
Hannah Sweet Potato
Hannah Sweets are cream colored with fairly smooth skin. Inside, the flesh is cream-white that becomes more yellow when cooked. It offers a lightly sweet flavor with dry texture that is great mashed, roasting in pieces or turning into fries.
Japanese Sweet Potato (Murasaki)
Japanese sweet potatoes, which includes the Murasaki variety, have reddish-purple skin with whitish flesh that turns golden when cooked. Its shape is more round than cylindrical. The flavor is very sweet and the texture is fairly firm. We think these taste best roasted or steamed.
Jewel Sweet Potato (Covington)
Jewels, which includes the Covington variety, have copper colored skin and deep orange flesh. When cooked, this sweet potato takes on a moist, fluffy texture and offers mildly sweet taste with subtle earthiness. This is a good all-purpose sweet potato. The moist flesh is good for boiling, baking, and adding to casseroles.
Purple Stokes Sweet Potato
Purple Stokes have a vibrant deep purple skin and purple flesh inside. Dryer, denser and richer in texture than other varieties, it offers a balanced sweetness with floral notes. It contains high levels of antioxidants making it one of the most nutritious varieties. The dryer texture of this potato lends better to high moisture cooking methods such as steaming, boiling, roasting or frying. They can also be used for baking but note that recipes with baking soda may turn this purple potato green!
Storing Sweet Potatoes
Sweet potatoes should be stored in a cool, dark, well-ventilated area away from strong heat sources. It is not recommended to store them in the refrigerator.