Place the berries in a single layer on a baking pan and place them in the freezer. Once they're frozen, put the berries in freezer containers or plastic freezer bags and seal. (Stored this way, berries will keep in the freezer for up to a year.)
In a large bowl combine the frozen berries, cold water, and frozen concentrate. Place half of the mixture in a food processor bowl. Cover and process until almost smooth. Repeat with remaining mixture. Serve immediately. If desired, scoop frozen mixture into cones. (Or, transfer mixture to a baking dish. Cover and freeze about 4 hours or until firm. Use within 2 days).