I know lots of brewers seriously question the need for a secondary fermentation. I am jumping on that train as far as I can, but I have a beer in my primary that I intend to add fruit to. For this reason alone, I am going to do a secondary fermenter to help get as much fruit/beer contact as I can.
So my plan was to pour my pasteurized fruit into the bottom of my glass carboy, then rack with an auto siphon on top of the fruit. Then, I would let the yeast create more CO2 from the fruit sugars, and then I would swirl the carboy around a little, to help the fruit mix around in the liquid once there is no oxygen left in the headspace.
But, obviously something could go wrong. The beer will be exposed to oxygen during the transfer process, which could destroy the beer (unlikely but always possible). Or any oxygen in the headspace could ruin my brew as I try to agitate the fruit. My idea was... How could I purge the headspace with CO2? I don't own a kegging/forced carb setup, but I do own a soda stream that no one uses. Could I possibly use this to push CO2 into the carboy after the beer and fruit is inside, thus hopefully pushing oxygen out? Or is this all a pipe dream and a waste of time?
I've read about the sterilized marble idea and that doesn't excite me at all. My only true options are soda stream or to just let it ride and hope for the best.