I'm using a filter for the first time. Setup is the source keg is hooked up at 2 psi and piped through a filter to the spear-side of another keg. The beer was cold from being in the fridge overnight and had not yet been carbonated. Everything was fine until I left the garage for longer than I thought I would.
When I returned it had finished pumping the beer from one keg to another and was slowly pushing CO2 though the filter and bubbling up through the keg, producing a nice layer of bubbles on the top.
I've read that it's bad to aerate the beer as it produces staling reactions, but I did it with CO2 instead of air. I tasted it afterwards and it definitely had changed the flavor for the worse. My question is, is the flavor change temporary and I've just given it a head start on the carbonating process, or did I just "stale" the beer?