Freezing whole berries is the fastest method and most excellent way to preserve the quality and freshness of the product. The method I've explained here works for freezing blackberries, blueberries, raspberries, and strawberries.
HERE'S ALL IT TAKES
Carefully wash berries and drain on an absorbent towel. Pat dry with another towel. Place dry berries on a cookie sheet lined with wax paper. Put in the freezer until frozen solid. Within the next 24 hours, package loosely in plastic bags and return to freezer.
It's always a good idea to measure out frozen foods as you are preparing to put them in bags. Divide the food into cooking portions. Also, make notes on the bag showing the name of the food, the amount and the date it was put up in the freezer. Some foods are best only frozen for a up to 6 months.