By: Diane Wright Hirsch, MPH
There is nothing quite like a fresh fall apple, crunchy sweet/tart and delicious. Fast forward to that supermarket apple in April. Mushy, grainy textured, with significantly less crunch and flavor. The season for apple growing usually comes to an end in November in Connecticut. Through the wonders of modern technologies and refrigeration, local orchards can keep apples long into winter and spring. But availability may come with a cost—flavor and texture may be altered.
So, why not take advantage of the abundance of local apples (and, perhaps pears as well) right now? Consider dehydrating them. A rather low-tech, almost food safety issue free, easy home food preservation method that can yield a sweet, midwinter snack.
Drying is one of the oldest methods of preserving foods—you will often see apple rings strung and hung up near the wood stove in displays of colonial kitchens. For moist foods, such as apples, dehydration includes increasing both the temperature of the food and air flow to allow for evaporation and removal of moisture.
Successful dehydration happens when you have the right balance of temperature and humidity. If there is too much humidity (which often plagues us in the Northeast) or too low a temperature, you may end up with moldy apples or fruit that could be contaminated with spoilage organisms or the bacteria that cause foodborne illness.
Dehydrating apples in your home kitchen
So, in your home kitchen you will need to employ both a source of heat and a method for removing the moisture from the air around the apples. The best and most efficient way to dry apples is to use a food dehydrator. These appliances are easy to find online and at retailers that cater to those who use dehydrated foods to lighten the load on camping or fishing trips. They range in size and cost. A small, stackable round unit will take up little space and cost as little as $30. You may often add more trays to increase your output. However, you do run the risk of uneven drying with these machines. Food closest to the heating element will dry fastest. Regular attention to rotating the trays is essential. This may be a good, less costly, way to get your feet wet.
Larger box type dehydrators with trays cost more ($200 or more). Some have timers; most have thermostats and more variations in heat settings. They may dehydrate more evenly, depending on the placement of the heat source—to the back vs the bottom or top of the unit.
You can also use your oven if you are just starting out and are not sure this is something that you will be doing on a regular basis. You will need to use an oven that can be set at a very low temperature—140-150 degrees F. Temperatures that are higher than this will lead to case hardening: the surface of the fruit dries and hardens while the interior stays moist, allowing for the growth of microorganisms and molds. A convection oven is great because of the increased airflow. But, you can also prop your oven door open a few inches and even place a fan to one side of the open door to drive off the moist air.
Preparing your apples
While most apples dry well, some prefer the quality of Gala, Fuji, Honeycrisp, Granny Smith, Empire or Cortland. Experiment to find your favorite.
Pick high quality apples, the fresher the better. Wash them well and remove any signs of decay. Slice in 1/8 to ½ inch slices. The thinner slices will dry firmer—like chips. You can peel the apples or leave the peels on. Peels can toughen during the drying process, so, again, experiment and see what you like best.
Pretreat the apple slices with a solution of lemon juice or ascorbic acid (vitamin C). This will help to minimize browning and may have some antimicrobial properties as well. If using ascorbic acid, stir 2 1/2 tablespoons of pure ascorbic acid crystals into one quart of cold water. For smaller batches prepare a solution using 3 3/4 teaspoons of pure ascorbic acid crystals per 2 cups of cold water. Alternatively, combine equal parts of bottled lemon juice with water (one cup water and one cup lemon juice). Soak the apple slices for 10 minutes, drain, and they are ready to dry.
Generally, dehydration of apples is accomplished at around 140 degrees F. It can take as little as 5 hours or as long as 24 hours depending on your dehydrator/oven, the humidity in the air that day, and the thickness of your apple slice. This alone may be a good reason to invest in a smaller dehydrator rather than keeping your oven on for hours and hours.
Once you think they are done (should at least be leathery if not crisp), let the apples cool. Place them in a glass jar or air tight plastic container for several days. If moisture begins to collect on the surface of the container, you have not dried the apples long enough. Put them in the dehydrator or oven for several more hours.
You can store dried apples at room temperature in a cool, dry, dark location. A glass jar or air tight plastic will work. Use freezer bags if you want to use plastic bags. Regular food storage bags may let moisture in. They will be fine to eat for six to twelve months. If there are signs of molding or spoilage, then discard them.
For more information about dehydrating apples or other foods, visit the UConn Food Safety website at www.foodsafety.uconn.edu or contact the Home and Garden Education Center at firstname.lastname@example.org or 1-877-486-6271.