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?
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.
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.