Walker said:
I'd say the temp might be an issue with a lager yeast. Room temp is way to warm for that yeast. It wants to work in the 48F-58F range (optimally 48F).
He also mentions that lager yeasts should utilize a VERY large starter, so maybe the lack of a starter and the warm temps have caused a problem?
-walker
I'm certain the temperature is NOT the problem (IFF wort temp at pitching was less than 37 deg C). I've used the barvarian yeast at warm temps before works great. If you look at the peer reviewed scientific literature about either basic science of yeast or brewing there are a lot of different viewpoints. I personally think Palmer is wrong and I've researched heat shock and growth properties of bacteria and yeast. It was a while back but there hasn't be a major paradigm shift in yeast growth curves probably decades.
First, lager yeast decrease their doubling rate as a function of temp. The lower the temp (to a point) the slower they will divide. Most yeast lager and ale yeast reach maximal division rate between 30 to 37 degrees C. This is well above room temp and well above lager temp. If you want to prove it...take a A600 reading every 30 min-1 hour at different temperatures. I've had one of my classes do this for a lab experiment...this is a standard microbiology experiment.
Second, lager yeast tolerate cold temperatures better than ale yeast. This does not mean they will not grow at warmer or are more efficeint at colder temperatures but we are exploiting a known trait to produce a better beer. To oversliplfy the exact cellular mechanisms...what you are doing is forcing the yeast to not prefer any one energy source.
Third, thermal shock can occur by either too much change in temperature either way. You don't want to be too high....42 deg C induced major changes in the proteomic landscape via induction of HSPs. Too cold also induces HSPs, and ribosomal RNA synthesis...but yeast don't usually die from too cold (unless frozen).
Finally, unless his wort was greater than 42 deg its doubtfull that his yeast died from temperature. What I'm worried about is the 2 days for the package to come alive. This yeast was a primary canidate for a starter! Make sure you have a well aereated starter that you continue to aereate throughout the growth. Aereration during the starter builds up glycogen that helps the yeast during the aerobic/anaerobic shift). The wort also sounds like it may have not had enough oxygen dissolved. From personal and helping others out....the barvarian yeast requires good aereation of the wort. Also a buddy of mine has used this yeast at room temperature to produce a good albiet dryer lager. The beer feremented out faster than the equivilent beer at colder temps (can provide graphs if necessary).
Pitch more yeast and aerate the beer! I think you had a old/bad batch of yeast. Look for the newest packet you can find that is not near the back of the fridge (sometime it get too cold and will decrease viablity).
Good luck! I'd write more but I have to get back to work.
-Eric
