I'm concerned. I know I'm not supposed to be, but I am. I'm attempting my first cider and I'm not sure it is going well. A week ago, I put 3 gallons of "all natural" cider into my 5 gallon glass carboy, added 3 tsp yeast nutrients and a vial of ale yeast. I had expected to see some activity when I woke up in the morning, but had none. Then I went away for 3 days. When I came back, I had some activity, but nothing too furious. Right now, I'm timing one bubble in the airlock every 20 seconds. Does this sound OK? Did I miss the really active fermentation? I thought cider was really active over a long time. Maybe I just need to understand what "active" means.