General Category > Yeast and Fermentation
No lager activity
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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