Can I store less then 5 gallons in a keg topping it off with CO2? I want to brew and have beer made, but I use 2 1/2 gallon kegs because my frig is small. I picked up a nice clean 5 gallon keg, and planned to store beer in it awaiting an empty 2 1/2 gallon keg.
There are a few issues with storing beer in any half full container. All of these issues are manageable.
The first issue is oxygenation, but if you flush the keg with CO2 it will be fine while it is in the keg. Storing the keg at room temperature will allow a little bit of additional fermentation and you will wind up with a thicker layer of dead yeast on the bottom. I always have at least some dead yeast on the bottom, but when I store at room temperature the layer is thicker.