batch size is 5 gallons.
I highly doubt that temp is the issue. While this is the first run for my homemade lager fermentation chamber, I tested it for 3 days before using it and it held temps perfectly - variation of about +- 3 degrees from target temp depending on when in the evening I remembered to change the ice out.
I was pretty careful about allowing the wort to cool all the way to lager temps before pitching. In fact, I may have pitched a bit cold as I set the thermostat to 46 F and let the wort continue to cool in the ferm. chamber for a couple hours before pitching. My imersion chiller had brought it to 62 F before transferring it to the carboy. After pitching, I raised the air temp to 48 F and pretty much held it there throughtout.
Furthermore, while I don't have any of the stick on temp gauges (ruined them all in water baths), I monitored the air temp fairly carefully and everytime I changed out the ice jugs, the chamber definitely felt cold. There is just no way it was off by that much. Certainly no way it was above 60 F. Besides, the airlock activity was never vigorous enough to make me think that the temp was too high.
Even then, I also suspected that the temp could be the culprit when I saw the activity slow so soon. So, I sanitized my digi thermometer probe and took a reading - 51 F, right on with the air temp readings (yes, I have calibrated it).
Meh, I'm not really worried anymore. Just kind of surprising.
Lesson learned: not having any homebrew to drink makes a homebrewer nervious about his/her homebrew.
I've started raising the temp up to 60 F now for a 36 hr. diacetyl rest. Then I will rack the fest and brew my doppelbock, which will be dumped on top of this yeast cake. At least that's the plan. Anyone have any thoughts on pro's and con's of yeast washing? How beneficial/necessary is it to remove the extra trub from the first batch?