I made my first 10 gallon ipa last weekend. I used a sanke keg with a rubber stopper and an air lock for a fermenter. I saw no activity in the air lock. My OG was 1.066. I just stole a sample out of it and showed a gravity of 1.010. Is there a chance that it fermented without moving the air lock because of all of the extra space in the keg? Besides adding additional yeast is there anyway to tell if the beer survived?