Sweet potatoes come in two varieties – orange or yellow fleshed. The orange fleshed are more common and sweeter than the starchy yellow fleshed type. Many people refer to orange fleshed sweet potatoes as yams, but yams are actually a much larger vegetable grown in Africa and Asia. A true yam can grow to weigh 100 pounds.
Orange fleshed sweet potatoes are loaded with beta-carotene, vitamin C, vitamin B6 and manganese. If you eat them with the skin on, they are a great source of fiber as well.
Sweet potatoes are available throughout the year but are what you might term in season in the fall and early winter.
When you buy sweet potatoes select those that are heavy for their size, hard, smooth skinned and free of blemishes, sunken areas or bruises. Bad spots can affect the flavor of the whole potato, even when cut out before cooking.
Because sweet potatoes have thin skins they are more susceptible to damage and spoil relatively quickly. The ideal place to store sweet potatoes is in a root cellar or cool pantry. Do not store them in the refrigerator because low temperatures will cause the sugars to turn to starch.
If kept cool (55 to 60 degrees F) sweet potatoes will keep for about 1 month. They will stay fresh for only a week or so when stored at room temperature.