Dehydrating food is a way of preparing food for use much later — for as long as a few years. Most fruits, blueberries included, easily withstand this process due to a high sugar and acid content. Dried blueberries also have the distinction of being among the easiest to prepare, since no slicing will be needed to make each piece similar in size.
Those preparing dried blueberries, either for survivalist purposes or as a healthy snack for active time outdoors, will not need a dehydrator — though it would help. These machines are useful and make the drying process more productive and less time-consuming; however, an oven set to its lowest temperature will do, leaving the door slightly ajar to let the heat escape. The ideal dehydrating temperature of this fruit is just 125°F (about 52°C).
A thorough washing of the very freshest blueberries is required to remove bacteria and produce the best final flavor and texture. To make sure bacteria does not set in, some boil the blueberries in water for just a half-minute or less to make sure that the skin is intact on each berry. Others skip that step, however, for fear that the dried blueberries will lose flavor. Before the berries go on, some lightly spray the dehydrator trays or cookie sheets with cooking spray to avoid any sticking. According to the Backpacking Chef Web site, crispier dried blueberries result from placing the fruit on the trays or sheets with the skins directly touching, not where the stems were attached.
The U.S. Highbush Blueberry Council, focusing on just that one species of fruit, asserts that dried blueberries are not just valuable for trail mix variety. Desserts using a dense batter like muffins or bagels are well-suited for the use of dried blueberries instead of the ordinary kind. Fresh or frozen blueberries could become damaged during baking, while the dehydrated fruit will become rehydrated during the baking process and maintain the best simulation of its original consistency.
Though their optimum drying temperatures and times will vary, blueberries can be dehydrated right alongside any other fruits like slices of banana, strawberry, apple and even the grapes that turn into raisins. Grapes and blueberries will be the easiest to prepare, though many of the other fruits will need to be sliced into same-sized portions for consistency's sake. Some fruits like peaches can take as long as a day and a half to fully dry out. Blueberries, by contrast, should be ready for testing in no more than 18 hours.