The airlock fell off of my bucket during the fermentation process for about 12 hours, does this mean my entire batch will be ruined?
it will depend on where it was located. If it’s near a high traffic area you might be at risk, but if it’s in a quiet dry area you’ll probably be fine.
Worst case scenario is you have a bit of a sour beer that you can fix by adding in some fruit concentrate to balance out any off flavors.
I would also suggest drinking the batch quickly as the longer it sits, the greater the chance any infection will become more pronounced.