mandoman
Well-Known Member
Another 'help me out here' thread.
When yeast are pitched into unfermented wort they begin to bud or reproduce asexually in the presence of oxygen. Once the oxygen is depleted they switch to anaerobic metabolism and create alcohol and co2. So, what I'm thinking is that the 'lag time' prior to what we call fermentation (bubbling, physical activity, etc.) has at least something, if not a lot, to do with the concentration of oxygen at initial pitch. I'm guessing this is why I've read that no lag time is not necessarily a good thing. The questions that come to mind are, 1) is there an ideal 'lag time' or initial o2 concentration for a given pitch rate/yeast health, 2) can this be easily determined given that we often use repitches and don't really know viability, cell counts, etc., 3) if you give a wort 'too much' o2 can this give you too high a pitch rate due to too much reproduction, and if so 4) if you pitch the 'right cell count' do yeast even need the o2 in the first place since they don't really need to reproduce or is this initial reproduction beneficial as the yeast adjust or somehow react to the wort and thus the subsequent reproduction is healthy in that it is specific?
I know, a lot of questions.
When yeast are pitched into unfermented wort they begin to bud or reproduce asexually in the presence of oxygen. Once the oxygen is depleted they switch to anaerobic metabolism and create alcohol and co2. So, what I'm thinking is that the 'lag time' prior to what we call fermentation (bubbling, physical activity, etc.) has at least something, if not a lot, to do with the concentration of oxygen at initial pitch. I'm guessing this is why I've read that no lag time is not necessarily a good thing. The questions that come to mind are, 1) is there an ideal 'lag time' or initial o2 concentration for a given pitch rate/yeast health, 2) can this be easily determined given that we often use repitches and don't really know viability, cell counts, etc., 3) if you give a wort 'too much' o2 can this give you too high a pitch rate due to too much reproduction, and if so 4) if you pitch the 'right cell count' do yeast even need the o2 in the first place since they don't really need to reproduce or is this initial reproduction beneficial as the yeast adjust or somehow react to the wort and thus the subsequent reproduction is healthy in that it is specific?
I know, a lot of questions.