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Jdub

older yeast

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question: i just brewed a MRB Sunday Morning Coming Down over the weekend. pitched a WLP001 Cal Ale yeast. Date was September 18-ish. No starter. aerated wort before pitching. brought yeast pack to room temp hours before pitching. shined a flashlight into LBK and have only seen a very thin bubbly layer on the wort that just appeared in the last 24 hours. not the vigorous krausen like most batches with fresh yeast. should i just let this play out? I have a US-05 pack i could throw in there right now, or i could leave it alone. i don't like to waste time, so i'm inclined to pitch another pack of yeast. what do y'all think? should i stop freaking out and just chill?

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Well, 05 is the same yeast so it wouldnt hurt to throw it in. That shouldve been more than enough yeast but god damn, its been days. Id chuck a pack in just to be sure. Although any layor of krausen is in fact krausen... give it til the morning then investigate.

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If there is a layer of trub on the bottom, then leave it alone.

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If you have Trub you have fermentation.  I have had batches that never formed a thick layer of krausen and then others that started that way and then all of a sudden overflowed.  Give it a week and then check your gravity, if it is close to FG then you are good.  If not by then, I would pitch the US-05.

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3 minutes ago, BDawg62 said:

If you have Trub you have fermentation.  I have had batches that never formed a thick layer of krausen and then others that started that way and then all of a sudden overflowed.  Give it a week and then check your gravity, if it is close to FG then you are good.  If not by then, I would pitch the US-05.

good advice. thanks!

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The only thing is that if the initial cell count was low you might get additional flavors from yeast growth phase compared with having a higher cell count. But it probably is to late to impact that. I agree, and would do the SG check as noted above with pitch as needed.

From dry yeast, my experience with US-05 is that is gives a pretty good start within 24 hours or even less so if the liquid one is the same this is a pretty long time for it to get going, but I have not used that exact one.

 

If this was purepitch, then this gives some indications on viability with time. If not, it refers you to Mr Malty for viability calculations with age.

So you could backtrack and see if there could have theoretically been an issue then compare with recipe builder pitch rate calc.

 

*********************optimistic***********************************

 

https://www.beeradvocate.com/community/threads/white-labs-purepitch-yeast-some-numbers.573302/

This says Purepitch has a package date and a "best before" date on the pack and that at the "best before" date  :

The “Best Before” date comes from hundreds of internal trials, ultimately showing that after five months in PurePitch® packaging the average viability of first generation yeast remains at more than 79%.

 

**********************pessimistic*******************************

 

But Mr Malty is less optimistic - presumably not allowing for the improvements in packaging.

Feeding the date into this gives viability of 0. Hmm.

https://www.morebeer.com/content/yeast_viability_calculator

 Also this might be of interest

https://eurekabrewing.wordpress.com/2012/11/18/yeast-basics-check-yeast-viability/

(you lose 50% in 60 days in fridge)

https://www.whitelabs.com/faq/general/how-much-yeast-my-white-labs-homebrew-purepitch

 

 

 

 

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update if anyone but me cares. full layer of krausen going on now. strange b/c i pitched on Sunday and wasn't a lot of activity until today. Now about 1/2 to 1 inch of krausen. crisis averted.

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I'll be watching if you don't mind. Sunday Morning is one I want to try at some point.

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