Pick Blueberries that are blue all over – do NOT select ones that have a greenish-white spot on the bottom; they are not ripe.
Blueberries should be stored unwashed in an open container in the refrigerator. Stored at room temperature, Blueberries deteriorate rapidly.
Washing adds moisture which will lead to molding. To freeze Blueberries, simply put unwashed into a plastic bag, seal and freeze. Wash just before using. This “dry packing” method allows the Blueberries to freeze individually and pour from the container like marbles. Washing before freezing causes the Blueberries to lump together.
If, however, you want the convenience of “ready to use” Blueberries, wash prior to freezing and dry one layer at a time and freeze one layer at a time on a cookie sheet before bagging for the freezer.