First of all, you should buy the fresh and very ripe summer blueberries in the season which will stay in good condition for a longer period of time and will not lose their taste even after months of freezing.
Make sure you have rinsed all summer blueberries in the cold water in order to remove any dust or dirt from their surface.
After rinsing the blueberries roughly in cold water, you should drain these blueberries in a colander. Keep waiting until you feel that all blueberries become completely dry.
Now you should take a sheet pan and spread all blueberries on it ensuring that you do not overlap them. Make sure you spread blueberries in a single layer which will keep every single blueberry in good condition as it will receive equal temperature in the refrigerator or freezer.
A single layer of blueberries on a sheet pan will also help in preventing them from striking or sticking with each other.
After putting the blueberries into the freezer in a single layer, you need to wait for at least 24 hours which is a sufficient time to freeze the blueberries.
Take out the sheet pan of blueberries from the freezer after 24 hours and put all these frozen blueberries in a freezer-safe, airtight container. Freezer bag is the best option for that purpose.
Make sure you have tried your level best to get as much air out of the freezer bag as possible which will keep in keeping the blueberries in good condition for a longer period of time.
After placing blueberries in an airtight freezer bag, you should now place it in the freezer and your blueberries will remain in good condition for about one year.