So I just brewed my first all grain batch, a Brown Ale with an OG of 1.050. I aerated with pure O2 for about 25 seconds then pitched dry US-05 (not rehydrated) onto the wort. I gave it a quick stir and capped the fermenter. That was on Saturday night.
Since then I have seen almost no fermentation. I was expecting with pure O2 and US-05 I would at the very least see krausen in my airlock but that is not the case. For the first 12 hours I kept the fermenter in my basement which sank to about 61F overnight. Fearing that was too cold I brought it upstairs to warm it up. The next morning the ambient temperature was 72F so I assume the beer was probably 69F or so. I left it there for a day and saw no activity. I cracked the top and saw a layer of krausen maybe 0.5" thick. It was far less than I was expecting. Still fearing a hot fermentation, I dragged the fermenter back to the basement where it now sits wrapped in blankets at a nice 65F.
My question is... should I be worried? I was lead to believe if I used pure o2 and US-05 I would need a blow off tube and should expect to wipe krausen off the ceiling. Thus far, I am underwhelmed and a little worried. Help!