General Category > Yeast and Fermentation

No lager activity

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davidgzach:

--- Quote from: theDarkSide on January 15, 2013, 06:35:31 AM ---I agree with Dave on waiting.  Even with a starter, it takes a couple days for krausen on mine to show.  Only problem is that it is going to be severely underpitched.

--- End quote ---

DarkSide reminded me that I would definitely perform a diacetyl rest for 2-3 days at 68F when the beer gets a few points above FG and then lager on the cake for at least 4 weeks to allow the yeast to finish cleaning up the beer.

Dave

a10t2:

--- Quote from: theDarkSide on January 15, 2013, 06:35:31 AM ---Only problem is that it is going to be severely underpitched.
--- End quote ---

I don't see how. At four months old, the smack packs were probably 80-90% viable. 3 * 80 billion / (19 L * 10°P) = 1.3 million/mL-°P.

theDarkSide:

--- Quote from: a10t2 on January 15, 2013, 08:30:40 AM ---
--- Quote from: theDarkSide on January 15, 2013, 06:35:31 AM ---Only problem is that it is going to be severely underpitched.
--- End quote ---

I don't see how. At four months old, the smack packs were probably 80-90% viable. 3 * 80 billion / (19 L * 10°P) = 1.3 million/mL-°P.

--- End quote ---
I'm not sure I can agree with the 80-90% viability after 4 months since they leave the plant at 95%, even though Wyeast guarantees it for 6 months.  And not knowing how it was handled getting to the store and into their fridge, as well as the package not swelling too much.  I think Mr. Malty putting it at 10% is a little extreme however. 

a10t2:
Yeah, the MrMalty/YeastCalc viability estimates are reasonable (though still low, IME) for stored slurry, but for a sealed, refrigerated, smack pack they're just ludicrous. Notice that it never drops *below* 10% either; a 4-year old pack/vial has the same viability as a 4-month old.

At any rate, even if you call it 65 billion cells per pack (10% loss/month) that's still over 1 million/mL-°P, which is fine for a low-gravity lager IMHO.

davidgzach:
a10,

I thought it was you that told me in another thread that yeast loses viability at 20%/month?  That would make it an underpitch, however not a dramatic underpitch.  But it would lend to no activity in 3 days starting at 48F.

Dave

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