[Shawn3997]

Just pitched a bock on a cake and gave it lots of O2 just in case it needed it.  Two days later and it still wasn't really taking off so I threw in more yeast.  To see the other side, I pitched another beer on a similar cake with no added oxygen and it took off within the same day.  Did I make a mistake by oxygenating?  Did that signal growth to the yeast that caused the lag?

[ynotbrusum]

Are you relying on airlock bubbles or are you looking at the fermentation, itself?  A small leak can render the airlock unreliable.  That said, how old was the yeast cake?  That could be your issue, though I have never seen a repitch of a healthy yeast not take off quickly, even for lagers.

[Shawn3997]

Are you relying on airlock bubbles or are you looking at the fermentation, itself?  A small leak can render the airlock unreliable.  That said, how old was the yeast cake?  That could be your issue, though I have never seen a repitch of a healthy yeast not take off quickly, even for lagers.

Both.  Yeast cake was only 4 days old but had been sitting under an inch of beer leftover from bottling.  I figured that'd be enough.  Just read an article telling me that I'm over-oxygenating anyways so that might be the problem.

[ynotbrusum]

Adding O2 from the cylinder?  Yea, that can get toxic, at least in theory.  I am not sure the saturation level that is achieved based on relative times and quantities per liter, but certainly it will easily exceed atmospheric levels when left on for too long.