To prepare your berries for dehydrating (or freezing), fill your dish sink about 1/2 full of cold water. Add in 3 T. of vinegar and let them set for 15-20 minutes. Drain the berries and lay them out on your dehydrator trays.
Now you can eat the dried fruit or you can store them for future use and rehydrate them. Dried blackberries can be stored for many years.
To rehydrate the blackberries, just place them in really hot water for about 15 minutes and then you can use them as you would any fresh berry.