I may be overthinking this, but that's kind of what we do, isn't it?
I pitched my Challenger Lager directly onto the yeast cake of the Vienna lager I brewed a couple of weeks ago. I did not bother to splash, shake or otherwise aerate the wort. Yeast uses oxygen during the lag phase to reproduce aerobically, generating enough yeast cells to consume the sugars in the wort. When the yeast has reached critical mass (or the oxygen runs out), it goes anaerobic and begins to consume sugars and produce alcohol and CO2. Somebody please correct me if I've gotten this wrong or missed something in my oversimplification.
I made the assumption that a yeast cake, by default, contains enough active cells to ferment a batch of wort. It just did. So, theoretically, it wouldn't need a lag/adaptive phase and thus wouldn't need added oxygen to reproduce. It should go straight to anaerobic fermentation. Mine sure did. I had steady burbling in the blowoff vessel in three hours.
The question that now bugs me is whether it started fermenting quickly because there was indeed a sufficient amount of yeast and it didn't need a lag time or additional oxygen to take off OR did it simply go anaerobic and start fermenting because there was no other choice, there wasn't enough oxygen to reproduce?
Now I'm wondering if I do this in the future should I go ahead and aerate or give the wort a shot of O2 just to be on the safe side? Or is my theory correct and the huge amount of yeast in the bottom of the fermenter ready to go without an adaptive phase and thus no need for aeration?
Chad
I pitched my Challenger Lager directly onto the yeast cake of the Vienna lager I brewed a couple of weeks ago. I did not bother to splash, shake or otherwise aerate the wort. Yeast uses oxygen during the lag phase to reproduce aerobically, generating enough yeast cells to consume the sugars in the wort. When the yeast has reached critical mass (or the oxygen runs out), it goes anaerobic and begins to consume sugars and produce alcohol and CO2. Somebody please correct me if I've gotten this wrong or missed something in my oversimplification.
I made the assumption that a yeast cake, by default, contains enough active cells to ferment a batch of wort. It just did. So, theoretically, it wouldn't need a lag/adaptive phase and thus wouldn't need added oxygen to reproduce. It should go straight to anaerobic fermentation. Mine sure did. I had steady burbling in the blowoff vessel in three hours.
The question that now bugs me is whether it started fermenting quickly because there was indeed a sufficient amount of yeast and it didn't need a lag time or additional oxygen to take off OR did it simply go anaerobic and start fermenting because there was no other choice, there wasn't enough oxygen to reproduce?
Now I'm wondering if I do this in the future should I go ahead and aerate or give the wort a shot of O2 just to be on the safe side? Or is my theory correct and the huge amount of yeast in the bottom of the fermenter ready to go without an adaptive phase and thus no need for aeration?
Chad