Onions (Allium cepa) are biennial plants with edible bulbs. They are related to the lily, and from their origins in Asia have spread across the globe. One of the first cultivated plants, the onion is related to some of my favorite herbs too: garlic, shallots, and chives. Its sharp flavor comes from volatile oils in the meat that contain sulfur compounds. These sulfur compounds produce an enzyme that causes us to tear up when cutting onions. Chemical warfare one is of the plants more effective defenses against predators.
How to Choose Onions
Look for onions with papery outer skins that feel heavy when you hold them in your palm. Onions should be juicy, and heavier onions will be juicier onions. Whole onions should never have a strong smell. That's a sure sign the skin has been torn or bruised. Avoid any onions that have started to sprout. Young onions are the sweetest, and sprouting is a sign of age. Sprouting also robs the onion of its flavorful juice.
Storing Whole Onions: Onions will keep for up to three months in your pantry, basement or garage if you observe three rules: Keep them dry, dark and cool. Airflow is also important; that's the reason onions are sold in mesh bags. Turn them once in a while. This will help extend their life.
Never store a whole onion in a plastic bag. Plastic will lock in moisture and gasses, causing premature aging and rot.
Don't store onions with potatoes. Potatoes and onions kept together will spoil much faster. Their combined gasses and the moisture released by the potatoes are a terrible environment for either vegetable.
Don't keep uncut onions in the refrigerator. It's too cold in the produce drawer. Exceptions to this are scallions and some of the sweet onion varieties.
Saving Onion Parts
Don't throw out the top, paper or outer skin of the onion. Freeze them for soup stock. The skins and top will help flavor your soup, and the outer skin (parchment) will give your stock a nice golden-brown color.
No Tears Onions
Although science may have had some recent breakthroughs in developing no-tears onions, for now we'll just have to rely on the tried and true methods of cutting conventional onions under running water (or placing them in the refrigerator for an hour before cutting). Another option is to buy onion goggles. These tight fitting goggles create a sealed environment around the eyes. They work, too -- if you don't mind looking like a WW1 fighter pilot.
Cutting round vegetables on a flat cutting board can be a challenge -- and dangerous, too. To avoid injury, cut onions in half and place the flat side on the countertop before slicing or chopping. This will make the process easier and safer.
Onions release sugars as they cook, so cooking enhances an onion's flavor. The process also makes the taste less pungent.
Always remember to monitor the heat closely when cooking onions to avoid burning them. Burnt onions are bitter. They look unappetizing, too. Lower heat and regular stirring is a good way to dissipate the escaping moisture in the onion and cook it to an even, golden brown. You can also bake them uncovered and on low heat in your oven.
Avoiding Onion Breath and Smelly Fingers
Onions release oils that are absorbed into the tissues of the mouth when they're eaten, which leads to onion breath. This can be camouflaged with mints, parsley, cloves or seeds like fennel, but basically the smell will dissipate in its own time.
The problem with stinky fingers from handling onions or garlic is similar. The onion oil is absorbed into your skin and lingers for a while. To minimize the absorption, rub olive oil on your hands before handling onions. This will create a barrier and limit the amount of onion oil that's absorbed. If you can still smell onion on your hands, a lemon juice rinse will help, as will rubbing salt or cornstarch on your palms and fingers.
Common Onion Varieties
Yellow cooking onions aren't the only types of onions out there by any means. White onions are a good substitute for yellow onions, are easy to find and work well in cooking where high heat is required.
For use raw, purple onions and yellow sweet onions are wonderful choices. Vidalia, Walla Walla, Imperial and Maui onions are all sweet varieties. They are more fragile than yellow or even purple onions and only last a few weeks once harvested, but they offer a lot of sweet onion flavor with no heat.
Need a cup of chopped onion? A good rule of thumb is to have one large onion on hand for every cup of chopped onion in a recipe.
- Onions are high in vitamin C.
- Onions are easy to grow in the garden in light, sandy soil.
- A medium sized onion contains only about 60 calories.
- Eating onions helps lower blood pressure, reduce cholesterol and promote heart health.