The More Common Types Of Onions
If asked what the different types of onions are, it's fair to answer, "In terms of what?" There are different ways in which different types of onions, different varieties of onions, or different members of the onion family can be described. The onion can be classified in terms of its appearance, its culinary use, or strictly in terms of its botanical characteristics. To keep things reasonably simple, only the more common types of onions are considered here.
Yellow Onions - Let's start with the yellow onion. This is the one you'll most often find in the produce section, at least as far as the larger onions are concerned. It is characterized by a yellowish to brownish paper-like outer skin, and flesh that is more of an off-white or white tinged with yellow, than simply white. The yellow onion has a pungent taste, and while can be eaten raw, usually in a salad, sandwich, or hamburger, is a good choice for stews and casserole dishes.
White Onions - Somewhat close to the yellow onion is the white onion, featuring, as you might have guessed, a very white exterior skin. The white onion is every bit as sharp tasting as is the yellow onion, maybe even more so. White onions are often the onion of choice when making French onion soup, although a restaurant that specializes in French cuisine may elect to use Spanish yellow onions in the French onion soup they serve. There is a Spanish white onion that seems to be a favorite in Mexican dishes, being especially tasteful when sautéed.
Red Onions - The red onion is often one of the larger onions you'll find on the grocery shelves. Red onions tend to be a bit milder and sweeter than their white or yellow cousins. The color of the outer skin is red in some cases, and closer to a purple in others. The flesh is usually white, with reddish or purplish streaks. Red onions are very popular for use in salads.
Sweet Onions - Not all onions are sharp tasting or pungent, in fact there is a category of onion plants generally referred to as sweet onions. Among the sweet onions, the Vidalia onion is probably the best know, especially in the southern part of the United States where it originated. The Vidalia is sweet enough to be eaten like an apple, which many people do. Another sweet onion, having West Coast origins, is the Walla Walla. Some prefer to use either the Vidalia or the Walla Walla in salads or onion soup because of their sweeter taste. Another sweet onion is the Maui onion, grown on the Hawaiian island of the same name. Finally, there is a sweet onion from Texas, so sweet it is generally referred to as a super sweet onion, and is called the "Supasweet".
One of the nicer characteristics of some of the sweet onions is they don't have to be peeled under water to keep your eyes from tearing up. When one slices an onion, cells in the onion's flesh are broken up and generate what are called sulphenic acids. These acids in turn react with a certain enzyme, producing a gas, know as LF gas, which is what causes out eyes to sting, making us "cry" when slicing onions.
These crying sessions are not so apt to happen when working with another category of onions, green onions. Green onions, also called scallions, are very young and tender onions. They are harvested before their leaves begin to turn, which is when many onions begin to develop their sharpest flavor characteristics.
Two close relative of the common garden onion are also worth mentioning, both of which generally taste quite a bit milder than most garden onions. These are shallots, which resemble a cluster of small onions, and leeks, which resemble - leeks. If shallots and leeks are to be classified as types of onions, and they certainly deserve to be, the same could probably be said for chives.