they chomp an onion bulb or garlic and they leave them to be ever after.

When you heat onion or garlic, a whole lot of chemical changes result in a number of new

compounds that replace previous compounds. Flavor, texture, consistency, color change.

Fortunately for us, the irritating substances quickly disappear and change into other chemicals .

Any cooked dish that contains onion and garlic becomes sweet—remember onion and garlic

soup? Raw onion contains 3 to 5 percent sugar but boiled onion only about half of that. The cooking

liquid absorbs the rest and that’s why onion soup tastes so sweet. In sautéed onion, while a lot of

moisture evaporates, the sugar becomes concentrated to about 10 percent in the pan. Caramelization

of sugar turns the onion brown. (The increasingly sweet taste while cooking onion is also due to a

newly created sugar, fructose.)

We use two types of onions in the kitchen: dry and fresh. These are commercial terms, and

the two types are hard to identify in the supermarket. Yet, the distinction is important. Dry onions,

also called storage onions, are summer crops, harvested in the fall, and these are the common yellow

onions we use in cooking. They have a long shelflife and can stay in your cool, dry pantry for

months. Dry onions are usually smaller and have a thicker, heavier outer skin than fresh onions do.

Fresh onions are a different variety, are winter crops and farmers harvest them between May

and August. Their shelflife, like fresh vegetables, is only a matter of weeks. We know fresh onions

as sweet onions, a relatively new marketing term referring to their less pungency compared to dried.

(

Another marketing term introduced recently as a result of an aggressive marketing strategy is

designer" onions.)

Some sweet onions are, indeed, quite sweet and have very little pungency. Their sugar

content must be at least 6 percent to deserve the name “sweet onion”, compared to 3 to 5 percent in

regular onion. Some exceptional sweet onions have as much as 15 percent sugar—almost as sweet

as an apple! They owe their mild disposition and low pungency to their low pyruvic acid content,

the chemical that causes their bite. Growing onions on low-sulfur soils results in their low

pungency. You can almost eat them like apples, though I wouldn’t suggest to include them in your

fruit bowl.

We use sweet onions mainly raw in salads, while dry onions are the true cooking onion.

TASTINGS Sweet onion in the U.S.

We have seven sweet-onion growing areas in the U.S. and distributors often sell

sweet onions by name, not as simple generic fresh onions. These are the Vidalia

from Georgia, Texas Spring Sweet from Texas, Carzalia Sweet from New Mexico,

California Sweet Imperials and Fresno Sweet from California, Walla Walla from

Washington and Maui from Hawaii. As long as they are fresh, they all are very

good, and you can barely tell the difference from one another.

Agronomists developed these fresh onions for three desirable characteristics: low pungency,

high sugar and large size. Only seven areas in the U.S. (see Sidebar) satisfy climatic and soil

conditions to produce these desirable sweet onions, so the supply is limited and prices are higher

than for dry cooking onions. During the off-season, distributors bring in sweet onions from Chile.

Cooking with sweet onions is a waste not only because they cost more but because dry onions lend

better flavor to cooked dishes.

The organic chemical pyruvic acid that produces pungency also acts as a preservative,

which explains why fresh onions having much less pungency spoil so much faster. Keep sweet

onions in your refrigerator or in a single layer in a net bag (or stocking), that you hang in a cool

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