Hello, while I was at work today, my son took out the bung to my Irish Red for a few minutes. My wife put it back as soon as she noticed which made me realize I really dont know much about the potential issues exposure to oxygen can cause (and how long is too long?).
I know contamination could happen from bacteria in the air and whatnot but what are the other bad things that could happen and is a couple of minute exposure long enough to cause a potential problem?
Stale or cardboard flavors is usually from oxygen post fermentation. Usually we are talking about splashing of the beer when transferring to a second vessel or bottling bucket/keg.
C02 does not seem to float off readily, witness when you open a bottle and the mist stays there. Probably the same in your carboy.
I was at the Jack Daniels distillery, and walked a catwalk between open topped fermenting tanks of corn mash. Each is covered by a foggy layer of CO2. It actually dampens the smell. The tour guide allowed us to draw our hands up through the mist to our faces - and experience an explosion of mash laden co2 rocking our sinuses like horseradish! I’ll smell that forever!