Food Information
Root Vegetables


The sweet potato is a member of the morning glory family. It originated in Central America but is now grown in all areas of the world that have subtropical climates. It is a near-perfect food and is a staple in many of the world's under developed nations.

We mistakenly call one type of sweet potato a yam. The yam is of a different botanical genus, but is often used as a substitute for the sweet potato.

There are two types of sweet potatoes. The ones that we often mistakenly call yams have a deep orange-colored flesh and are very moist and sweet when cooked. They are grown in most of the southern states, with North Carolina, California, and Louisiana as the top producers. Thanks to a curing process, these sweet potatoes are available twelve months of the year.

The other type of sweet potato, which is known as the white sweet or Jersey sweet, is pale yellow or off-white in flesh color. These are not nearly as moist and sweet as the orange-fleshed variety and, except for limited pockets of regional preference (Philadelphia and South Jersey), have been almost completely displaced. Yet in Grandma's day the white sweets had about 90 percent of the market.

While sweet potatoes are available year-round, the two lightest months are June and July. During those months they are nearly a year old and the quality slips as the price rises. The most flavorful sweet potatoes arrive in market during August, September, and October. These are uncured and shipped to market directly from the field.

Freshly harvested sweet potatoes have a very short shelf life. Because they have a very high moisture content, they are prone to spot and decay. At best they last four to six weeks before they start to break down. By placing them in a kiln and removing much of this moisture, their shelf life can be extended from a few weeks to more than eight months. Kiln dried sweet potatoes are called cured; those that are not kiln dried are called uncured.

The cured sweet potato isn't quite as soft and moist as the uncured sweet potato; so those that are purchased from August through October will have the best flavor. All the sweet potatoes that are in market during that three month period are uncured; those sold from November until the following August, when the new crop arrives, are cured. There is only one crop per year.

Sweet potatoes are a subtropical vegetable that thrive in warm weather and can't tolerate the cold. Never store them in the refrigerator or they will cut black after cooking. Sweet potatoes are almost as sensitive to refrigeration as bananas are.

When selecting sweet potatoes, always choose those that are firm and shapely and have clear, unmarked skins. Those of medium size are your best bet if you are going to bake them whole, but they usually sell at premium prices. Very small ones taste fine, but may be more trouble to prepare than they are worth. Jumbo ones are good for boiling but take a long time to bake. However, the jumbos usually sell for about half the price of medium sweet potatoes, at least at the wholesale level.

WHEN TO BUY: Available year-round but at peak in August, September and October
WHAT TO LOOK FOR: Firm, shapely vegetables of medium size with clear, unmarked skins
HOW TO STORE: Do not refrigerate

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