I added 1 (one) lbs of frozen blueberries into the secondary, 5 gallon glass carboy. I suspended the blueberries in muslin bag. I put bag into carboy and added the blueberries a few at a time. yes tedious. I held the bag in place by draping it over the opening and placing rubber stopper in carboy.
however when I put blueberries into carboy fermentation started again. I was a little concerned but I relaxed, had a home brew, practiced good hygiene, and carried on.
after I week transferred to a keg for final conditioning. so far it tastes great,slight blueberry taste and not overwhelming and it did not turn sour which was my concern.
the frozen blueberries were my choice because they are 'flashed pasteurized" when frozen. I was a pain to get blueberries out. if friends like the beer next time ill brew a full 10 gallons and add blueberries to brite tank.