Lager yeast viability question

[irununo]

I bought a Wyeast bohemian lager pack with a manufacturing date of 12/4/2013 in order to brew an all grain Oktoberfest. Mr Malty said it had 20% viability and the calculator from this site said 40%. Either way, I made a 1.5 liter starter and had it spinning on my stir plate for 48hrs with no krausen whatsoever. The next morning (frustrated with the purchase) I went to dump it but it had some foam. Instead of leaving it spinning I decided to throw it in the fridge to decant and step up to 2 liters for the targeted 383 billion cells. I ended up waiting 3 days with the starter in the fridge (life and work interfering with my beer) and on the third day, found that it was still actively fermenting in the fridge.
So now its the sixth day since I opened the pack and its in a 2 liter starter spinning on my stir plate.

Does anybody have any opinion on whether I should use this yeast or get a new pack? I'm concerned with the manufacturing date, the slow start, all the time I had it waiting in that 1.5L starter and the cell count. I am encouraged because of the activity in my fridge (I didn't even have my temp controller on) but I thought it would have exhausted all that sugar and started to starve. I would hate to brew this Oktoberfest and find out months later that I should have spent $8 for fresh yeast.

I apologize for excessive rambling and thanks.

 

[Cyclman]

For a lager, I wouldn't risk it.

 

[sfgoat]

If you are concerned then get a new pack. Personally I'd probably step it up one more time and use it. I've found the bohemian lager yeast to be quite resilient.

 

[duboman]

If you have the time, decant and add another liter of wort and let it ferment.

Just because it took a bit to start initially it did and produced more new viable yeast. ( that's what a starters for anyways)

I'd have no issue using this yeast at all with another step and have done this before with no ill effects


Sent from the Commune

 

[irununo]

Thanks everybody for the help. I decided to step it up a third time and am in the middle of a fantastic brew day. Thanks again.

 

[jdauria]

Also when using a stir plate, you don't always seen a krausen as it gets stirred back into the mix, plus being lager yeast, thus bottom fermenting yeast, you probably would have not gotten one anyway.