Rinsed Yeast -- No Fermentation

I rinsed some yeast that had fermented a munich helles and repitched it into a new batch of dunkel. The yeast had been in the helles carboy for three weeks when I crash cooled the batch to 40 F from 50 F. I rinsed the yeast and put immediately into the refrigerator and pitched the next day. I used 120 mL of thick yeast slurry per the instructions from Mr. Malty Yeast Calculator. 54 hours later there are still no signs of fermentation. I know rinsed yeast that has been saved for several months may take this long to show signs of fermentation, but I thought this batch would jump into action immediately given my brief turnaround. I don't want my batch of dunkel to go to waste, so I was wondering if I should go to the LHS and buy a smack pack to pitch. Do I have time for a starter or is every hour critical now because of the potential for contamination? My carboy is sitting in my fermenting fridge at 50F with a blow-off tube extending from the carboy to a vessel of sanitized water. Did crash cooling kill my yeast? Any thoughts, warnings, predictions, advice would be welcome.

I think high temperatures would harm the yeast not low... When you washed the yeast, did you use water lower than 80 degrees?

Did you wake the yeast up in a starter, and if so, for how long? Even for washed yeast, you may need to give an average starter two days BEFORE you brew and pitch. Also - and I just ran into this myself - if you were trying to wake the starter at the same 50 degrees that you planned to ferment at, even with a healthy starter volume, you might need several days for the yeast to wake up and become active.

Well, 60 hours later and there's finally some krausen and activity. I agree that getting the rinsed yeast going in a yeast starter would prevent such a sluggish fermentation start. I'm just pleased that it's going and I don't have to pitch more yeast.

philbert119 said:

Well, 60 hours later and there's finally some krausen and activity. I agree that getting the rinsed yeast going in a yeast starter would prevent such a sluggish fermentation start. I'm just pleased that it's going and I don't have to pitch more yeast.

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Glad to hear...the lag was probably more an effect of the fact that you were using a lager yeast (which necessitates a lower temp) and not pitch rate.

Even under ideal conditions (not saying yours wasn't optimal), I don't think lager fermentations tend to be explosive like ale fermentation can be.