Michigan State University Extension
Preserving Food Safely - 01600656
10/13/97
Late maturing varieties of apples will store for use
throughout the winter if the fruit is hard, mature and in
perfect condition. Apples picked too green are subject to a
number of storage disorders, such as scald and bitter pit;
if picked beyond maturity, they quickly become overripe in
storage.
Cool as quickly as possible after harvest for best
results. For most varieties of apples, the optimum storage
temperature is 30 to 32 degrees Fahrenheit with a 90%
relative humidity. Higher storage temperatures reduce the
storage life considerably, and apples ripen twice as fast
at 40 degrees Fahrenheit as at 32 degrees Fahrenheit.
Apples can be stored outdoors in insulated boxes or
straw-lined pits or buried containers as long as the outside
temperatures are above 10 degrees Fahrenheit. They will
last longer and retain more flavor if kept in a fruit
cellar in plastic bags or in cardboard boxes lined with
plastic sheets. However, the cardboard box and plastic bags
or liners must be perforated to allow air circulation. If
the fruits are individually wrapped in tissue paper or
newspaper before being placed in boxes or baskets, better
results will be achieved. Plastic liners help maintain high
humidity and prevent the apples from being affected by the
surrounding air. The balance of humidity is subtle;
excess humidity will encourage decay, and insufficient
humidity will encourage shriveling.
Avoid storing apples too long and regularly check for
signs of spoilage. Mustiness will spread to healthy
specimens. Storage duration depends on the variety.