Onion
lovers once had to hold out until April or May for sweet
onions like the
Maui and Vidalia, or June
for the Walla Walla, but the wait is over. Several varieties,
developed during the past 17 years, have become popular.
We have the Texas 1015, usually planted around Oct. 15
(and that’s why it is called the 1015). It’s available
March to June. Then there’s the Mayan Sweet, in markets
September through April; and the Bermuda onion, which has
been axed from most growers’ fields because of low
yield.
With all sweet onions, it’s location, location, location.
The climate and soil are what matter. Most sweet onions
are grown from a seed variety called
Granex, which is the combination of a round-topped sweet onion called a Grano
and the flat-shape Bermuda onion.
In the Walla Walla Valley of Washington State, 60 growers on 1,200 acres grow
Walla Walla sweet onions in the perfect climate, in volcanic ash soil. The Vidalia
onion is grown in a 20-county radius of Toombs County, Ga., where the soil and
the climate are especially friendly to the Granex seed. The Texas 1015 and the
California Imperial Sweet have similar stories.
So why are these varieties sweeter than your average yellow onion? Some of
the more common pungent varieties of onions actually have higher sugar levels
than
sweet onions. But what matters more is the amount of sulfur compounds in the
soil where the onions are grown; these transfer to the onion’s bulbs. The
concentration of pyruvic acid in an onion bulb measures pungency. Simply put,
higher amounts of pungency in the onions mask the sugars, so the onions taste “hot.” So
with sweet onions, it is the absence of pungency, the lower levels of sulfur,
that allows the sugar flavor to please your palate. |
 Then
there is the onion that breaks all the sweet onion rules
with a real sugar level of up to15 percent. The OSO Sweet
onion, known as “the winter sweet onion,” is
available January through March. It took $10 million
and 10 years to perfect the seed, and by 1989, it was
ready
to plant in the foothills of the Andes Mountains in Chile.
There, the warm days and cool nights provide the ideal
climate to retain a high-sugar content and crisp texture.
The soil is volcanic and mineral-rich, which give the
onion a mild, sweet flavor. The water that flows down
from the
Andes is crystal clear and pure, and it is the only water
used to irrigate OSO Sweet Onions.
Sweet onions are fresher than regular onions and are more susceptible to bruising.
Look for firm, dry onions with shiny skins. Check the root end of the bulb for
any signs of breakdown or decay, such as gray mold. On the top of the onion,
check for moisture and softness by pressing in with the thumb and forefinger
near the stem. It should be firm and dry. At home, store them in a cool, dry,
airy location. Keep them away from tubers or other dry vegetables. If you are
planning long-term storage, check them periodically. Cut onions should be wrapped
in plastic and refrigerated. They can be refrigerated up to a week.
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