Apples like the cold. Not extreme cold—freezing them uncooked ruptures all their cells, ruining them. Cold that hovers above freezing, though, retains the quality of your apples and extends their life. Where you store apples and how long they'll last depends on how many you have, what type of apple you have and when you expect to eat them up.
If you are planning to eat your apples soon and don't have very many to store, the refrigerator is the best place for them. Some refrigerators have crispers for fruit and vegetable storage. The crispers might have a control to help you manage the amount of humidity inside. Consult the refrigerator's manual for advice on controlling humidity for apples. Generally, apples don't like the very driest settings because they'll shrivel. Storage in perforated plastic bags will help compensate for refrigerators with low humidity.
Apples interact in a couple of ways with other fruits and vegetables, so apples need to be segregated in the refrigerator. First, they emit a chemical called ethylene, which can be absorbed by other produce, including carrots (they become bitter), lettuce (it gets brown spots) and broccoli (it turns yellow).
Apple odors can be absorbed by other produce—cabbage, carrots and onions—affecting taste. Besides segregating the apples, putting an open box of baking soda in the refrigerator can help solve the problem. Of course, given concerns about humidity and ethylene, bagging the apples for refrigerator storage is the best idea.
For long-term apple storage, start out with good candidates. They shouldn't be damaged, they shouldn't be fully ripe and the core area shouldn't look glassy. Glassiness means the apple won't store well. Good candidates for longer-term storage will also be apples that are late-season apples such as Fuji and Granny Smith. Trees that fruit early aren't good candidates.
If you don't have a root cellar, a basement, storage room or porch might work. You want the temperature to hover around freezing. (Apples freeze at a slightly lower temperature than water.) Covering them with straw might help protect them from a freeze, while allowing them to be stored in an unheated place. Again, segregate the apples from other produce. Remember that the environment needs to be humid.
Ripeness and Storage
Many apple varieties have more than one color. The dominant color is called the overcolor. The background color or undercolor is the color that shows beneath. Ripe red apples will have a green-yellow undercolor, while less ripe red apples will have a green background color and the fruit will be firm. If you are eating apples soon, pick the ripe apples. For longer-term storage, pick those that are not fully ripe.