The apple crop is plentiful this year in Northeast Wisconsin. Here are some tips for storing apples.
• The length of time apples remain good in storage depends on the apple cultivars, stage of maturity at picking, handling before storage, how soon they are cooled down, and the temperature and humidity of the storage area.
• If large quantities are to be stored for an extended period of time, selecting the proper cultivar is important. Some Sort the apples that are to be stored. Remove any that are bruised, cut, or show signs of decay. Plan to consume the larger fruit of any cultivar first, saving the smaller ones for later in the season. The larger apples are usually the first to lose their quality and show signs of internal breakdown. Low temperature slows the respiration rate and preserves good quality.
• Apples last several times longer at 32°F than they do at 70°F. Most apple cultivars should be stored at 30 to 32°F for optimum storage. However, McIntosh apples should be kept around 36°F. If possible, the storage temperature should remain constant. The freezing temperature of apples is 27.8 to 29.4°F, so it is best not to store apples in unheated locations where the temperature may get too low. Once thawed, frozen apples deteriorate quickly, resulting in softening of flesh and loss of texture. Relative humidity must be kept high, between 90 and 95 percent, in a fruit storage area. If the humidity is not maintained, apples dehydrate and shrivel, particularly Golden delicious.
• Apples can be kept well in humid cellars that maintain a cool temperature below 40°F. They also can be stored in unheated outbuildings or garages, in Styrofoam chests, or with hay or other insulating materials piled around them to prevent them from freezing.
Unfortunately, most homes are not equipped for proper apple storage. It may not be economically wise to buy large quantities of apples unless proper storage is available or the fruit will be used in a short period of time. Small quantities of apples are usually sold in perforated plastic bags. Storing the fruit in these or similar bags in a cool refrigerator will greatly reduce the respiration rate and the fruit should remain firm and crisp until used. The atmosphere inside the plastic bags is usually quite humid, whereas the atmosphere of the refrigerator has a lower humidity that tends to pull moisture out of the fruit, causing it to shrivel. The holes in the bags eliminate the buildup of carbon dioxide and excess moisture inside the plastic bags. Apples also can be stored in perforated polyethylene bags. However, the bags should not be tied shut. After the fruit has cooled down, the open ends should be folded over.