FoodFood InformationVegetablesRoot 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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