Onions are cheap, usually even cheaper in bulk, and the basis for many dishes. If you cook from scratch much, chances are that you are faced with a choice between stocking up on onions and having to go to the store for them every few days. And you may have found that if you stock up, the last of your onions start to sprout before you get around to using them. If, on the other hand, you are one of the many who only use onions occasionally, you may also find it hard to keep them without sprouting them.
Onions can be kept fresh for a long time, if you know what to do. Here is how.
1. Store in a cool, dry place.
The papery outer layer of an onion's skin gives it its own natural packaging. This packaging might as well come with a "Refrigerate after opening" label. Onions should not be refrigerated until they have been peeled or cut. However, they should not be heavily exposed to heat or direct sunlight, either.
Unpeeled, uncut onions should be stored in a cool, dry, place, such as a cupboard or pantry. They should not be kept in plastic bags or containers. Plastic traps moisture from the air and the onion itself. Onions stored long in plastic, outside of the freezer, are liable to mold and sprout. A brown paper bag is ideal. Onions may also be stored in a cloth bag or cardboard box. Properly stored onions keep well for four to six weeks.
2. Refrigerate after opening, and use quickly.
If you need only part of an onion for something you are cooking, cut off that part before peeling it. Leave the rest of the onion unpeeled, and store it in the refrigerator. Unlike uncut onion, cut onion should be wrapped in plastic or stored in a plastic container or ziplock bag. Use within two days.
3. Freeze it.
If you have cut onion that you will not be able to use within two days, it should be frozen. Onion becomes mushier when it has been frozen and thawed. Large pieces do not maintain their shape well. This is not something to do if you want to use the onion as raw onion rings.
However, chopped onion will still be recognizably the same, and if frozen when fresh, most of the flavor and nutritional value will still be there. Some cooks choose to chop and freeze onions ahead of time, so as to save steps when cooking.
To freeze onion, begin by peeling it and chopping it into bits. Place the chopped onion in a ziplock bag. Press the air out of the bag, seal, label, and freeze. Onion will keep this way for as long as several months.
These three tips should have you saying good-bye to moldy and sprouted onions. If stored in a cool, dry place when whole, refrigerated and used quickly after cutting, or chopped up and frozen, onions remain fresh until they are needed.
"Frozen onion" and "Keep onions in the dark" posts at http://www.lovefoodhatewaste.com/storage_and_tools?food=81