An ancient food-preservation method, dehydration is still an economical and effective way to safely preserve many foods today. Dried goji berries, sometimes called wolf berries, are very much like raisins. You can dry them using the sun, your oven or a dehydrator, and with proper storage conditions, they should keep for a year.
To test for doneness with any drying method, remove a few berries from the drying tray and allow them to cool. Warm fruit tends to be softer and more pliable than cooled, so it's easy to over-dry them. Squeeze the cooled berries in your hand and release. If your hand remains dry with no wet or juicy spots and the fruit springs back to its wrinkled shape, drying is complete.
Using hot water, thoroughly wash and rinse all pans and racks you'll place the berries on during the dehydration process.
Sort the goji berries, discarding damaged fruit. Remove any pieces of stems and leaves. Wash the berries in a colander under cold running water.
Crack the skins of the berries to speed the drying process. Fill a large saucepan or soup pot half full of water and bring it to a rapid boil. Have a large bowl of ice water ready on the counter. Immerse the berries in the boiling water for 30 to 60 seconds, then remove them from the boiling water with a slotted spoon and immediately place them in the ice water. The rapid temperature change causes the skins to crack, which hastens dehydration.
Goji berries typically do not require treatment to prohibit discoloration because they are rich in vitamin C, which naturally prevents browning. Their bright red-orange color does darken during dehydration.
Place wire racks on large baking sheets or jelly roll pans. Place the goji berries in a single layer on the wire racks.
Cover the berries with a layer of cheesecloth to keep insects away. Secure the cheesecloth around the edges of the pans with spring-type clothespins or tape.
Set the pans of berries in a clear, sunny location away from human and pet traffic. Turn the fruit once or twice daily to encourage even drying. Depending on the humidity and temperature, goji berries take two to four days of full sun to dry to a raisin-like consistency. Begin testing the berries as soon as they become wrinkled.
If you want a sheltered location to dry a few berries, place the cheesecloth-covered pan of berries on the dashboard of your car. Leave the windows partly open for airflow. Turn the car around in the morning and afternoon so that the window always faces direct sun.
Preheat a regular oven to 140 degrees Fahrenheit. A convection oven may be set about 10 degrees lower -- check the oven manual for specific recommendations. Arrange the oven racks near the center of the oven.
Place the wire racks on large, flat pans, then place a single layer of prepared berries on the wire racks.
Place the pans in the oven, making sure there is at least 1 1/2 inches on all sides between the oven wall and the edges of the pans. Leave the oven door slightly ajar during the drying process.
Check the berries regularly, turning them as necessary so they dry evenly. Berries in a convection oven may not need turning, because the fan inside a convection oven constantly moves the air. When the berries appear wrinkled, begin testing for doneness. Remove the berries as soon as they test done.
Place a single layer of prepared berries on clean dehydrator trays.
Slide the trays into the dehydrator. If your dehydrator is a stacking unit, stack the trays and place the cover over them. Leave the air vent on the cover open for maximum air flow. Set the appliance on medium or low, depending on the model.
Check the berries regularly. Rearrange the trays as necessary to promote even drying.
Test for dryness and remove the berries as soon as they are done.