US-05 + O2 Aeration = No visible fermentation ??

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!

No worries, its fine.

The reason to oxygenate is not to have more violent fermentations but rather to give your yeast the best possible environment to do their work. This will lead to fewer off-flavor compounds.

Well I don't want a violent fermentation but this is like the least active fermentation I have had yet... or it appears to be.

I guess I will just RDWHAHB and wait it out.

If there is an issue with your fermentation, you can be 99% sure it isn't because you oxygenated - adding O2 is good for the yeast.

How old were the yeast? And how much yeast did you pitch, for how many gallons of wort?

Guess everything worked out fine even though I didn't see any activity at all. It has been 7 days. I started fermentation around 62F and then brought it up to 70F to finish over the past week.

My OG was 1.050 and I just measured my FG... 1.012 !!!!! Everything tastes great! I am going to check this again tomorrow and Monday and if things have plateaued, MY FIRST AG BATCH WILL BE BOTTLED

I've been having long lag times w/ US-05 lately, but all the beers have turned out fine.

Everything tastes great!

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Good to hear!

The amount of krausen you are experiencing in a given brew is not always related to attenuation levels.

I also would recommend against moving the fermenter throughout the house all day along and just find a place where the temperatures stay relatively constant.