I've reviewed all the starter posts, but still have a couple of questions, since I'm new at this. Just got an e-bay stir plate two weeks ago.
1. When using a stir plate and fermenting out a large starter, do you keep the stir plate operating then entire time or is it better to turn it off after 18-20 hours once CO2 is being given off.
2. How much yeast is too much? Jamil recommends using a larger starter than normal if fermenting out. I'm making a lager with 20% more wort than the calculator computes because of this. Okay?
3. In repitching from a previous batch of Munich Helles, I carefully measured the amount of yeast remaining in terms of ml. of thick yeast and pitched accordingly. But as this was a lager yeast (WLP830), I think it was more viable than the calculator gave it credit for. It was a month old, but very white with no discernable color change.
With my original starter (2 vials 830 into 3 qts., shaking every 30 min.), pitching at 46 F. into O2 aerated wort (90 seconds at moderate flow), it took 30 hours to achieve fermentation. With the second batch of Helles (same size), repitching 300 ml. of thick yeast, same pitch temp and O2, the fermentation took off in under 12 hours. Does this sound normal? They were supposed to be about the same amount of cells, yet more than a factor of two difference in lag time.