dehydrating yeast - did I kill them?

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stever1000

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Long story short my pump got clogged and I wasn't able to chill my wort, so I put it outside to cool overnight. Before this happened I started rehydrating the yeast to pitch.
With the pump not working I forgot about the yeast and it sat overnight at room temperature
i pitched it this morning but the top was a bit bubbly...now I'm wondering if the yeast are all dead??

It was belle Samson if that makes any difference
 

LBussy

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They are not happy, that's for sure. Chances are there will be some viable yeast left but you will have a sluggish start/fermentation compared to properly rehydrated yeast.
 

skraeling

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Could always just add more yeast immediately?
 

Setsumi

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They are not happy, that's for sure. Chances are there will be some viable yeast left but you will have a sluggish start/fermentation compared to properly rehydrated yeast.
I dissagree, the yeast would be fine, as long as you kept it covered to minimize contamination..... but even that would not be a big issue in most cases.
 

LBussy

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I dissagree, the yeast would be fine, as long as you kept it covered to minimize contamination..... but even that would not be a big issue in most cases.
You can disagree with me, but you will also have to disagree with yeast manufacturers and yeast experts.

"Yeast cells should not remain in [warm water] more than 30 min since they would tend to use up their reserve materials."
Fleet, G. (2002). Wine microbiology and biotechnology. London New York: Taylor & Francis.

"Leave the yeast cells not more than 30 min in this suspension to avoid using up their reserve material"
König, H., Unden, G. & Fröhlich, J. (2009). Biology of microorganisms on grapes, in must and in wine. Berlin: Springer-Verlag.

and of course:

"Once the yeast is ready, add it to the wort as soon as possible. At warm temperatures, the yeast cells quickly use up their energy resources."
White, C. & Zainasheff, J. (2010). Yeast : the practical guide to beer fermentation. Boulder, CO: Brewers Publications.

...I could go on.

Of course you're probably an expert too.
 
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stever1000

stever1000

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So if they use up their reserve materials, they die? :(
 

LBussy

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So if they use up their reserve materials, they die? :(
They can; they can go dormant eliminating the advantage that dry yeast provides most likely. You go from having all of those very active yeast cells to having a tablespoon of hungry grumpy, tired ones. I suspect it can also cause mutants which may be less capable of reproducing later on. This is me talking - the literature has less information on this than I'd like.

Re-pitch if you can. You'll be fine after that.
 
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stever1000

stever1000

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They can; they can go dormant eliminating the advantage that dry yeast provides most likely. You go from having all of those very active yeast cells to having a tablespoon of hungry grumpy, tired ones. I suspect it can also cause mutants which may be less capable of reproducing later on. This is me talking - the literature has less information on this than I'd like.

Re-pitch if you can. You'll be fine after that.
I have a starter going now but wont be able to pitch until tomorrow night at minimum. Fingers crossed this works out...
 

LBussy

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I have a starter going now but wont be able to pitch until tomorrow night at minimum. Fingers crossed this works out...
Putting on my Judge hat ... provided you maintain sanitation, a potential issue would be creation of esters in excess of that which would be normal for that yeast. There's a fair chance it will clean itself up too. Other than that I think you will be fine.
 
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stever1000

stever1000

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Putting on my Judge hat ... provided you maintain sanitation, a potential issue would be creation of esters in excess of that which would be normal for that yeast. There's a fair chance it will clean itself up too. Other than that I think you will be fine.
The excess esters would be created because the first yeast are so stressed, they are creating the esters. And because its for such a long time, they create many esters? Do I understand?

So even if my second yeast works, the beer may be off because of the initial stress? :(
 

LBussy

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Yes, stressed yeast may create excessive esters. These are often taken back up late in fermentation however so you just never know.

Given that esters and phenols are part of the desirable profile of this yeast, it's just really hard to say whether it will be "too much."

ETA: If you can, you might consider ramping up temps to around 74-75 degrees after a couple-three days to allow the yeast to suck up some of those by-products and avoid a stuck ferment.
 
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stever1000

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Yes, stressed yeast may create excessive esters. These are often taken back up late in fermentation however so you just never know.

Given that esters and phenols are part of the desirable profile of this yeast, it's just really hard to say whether it will be "too much."

ETA: If you can, you might consider ramping up temps to around 74-75 degrees after a couple-three days to allow the yeast to suck up some of those by-products and avoid a stuck ferment.
Thanks for the info, I will ramp up the temperature today/tomorrow after I pitch the new yeast
 

kh54s10

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IMO, The original yeast did use up the engineered reserves. Is it best to use that way - no. Are the yeast dead - no. Will it ferment the beer - yes. Will it make bad beer - no. Will the beer be the best it could be - no. How bad will be any off flavors - not too bad.

Adding new yeast is not a bad idea as long as it is done pretty soon. If the yeast already pitched do a fair amount of the fermentation, pitching more yeast is just a waste of good yeast.

As to ramping up the temperature. Do not do this until you are very close to final gravity. Too soon and you will produce off flavors. Mid sixties is best for most ale yeasts and I would keep it there until you reach final gravity. IMO, off flavors from warm fermentation would be worse than anything previous in this session.
 

LBussy

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I agree with all kh has said. A hydrometer is your friend here. Prepping a second dose of yeast is not wasted time IMHO. If you need it, you want it to be ready.

How has it been acting? Krausen at all?
 
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stever1000

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I agree with all kh has said. A hydrometer is your friend here. Prepping a second dose of yeast is not wasted time IMHO. If you need it, you want it to be ready.

How has it been acting? Krausen at all?
No activity in the airlock, I am going to open the lid and check for krausen this evening
 

LBussy

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Yeah, check gravity while you are there. If you are close to terminal gravity, time to raise the temp a bit. If not, re-pitch and let it go a few more days.
 
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stever1000

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Sounds good, I will report back tonight :mug:
 

kh54s10

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Another "no activity in the airlock" thread. Especially when using a bucket... I expect that when you open it you will see that fermentation has started. Another leaky bucket seal....

I still say that leaving the rehydrated yeast so long was not best, but I don't think any real harm can come from that happening.
 
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stever1000

stever1000

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Another "no activity in the airlock" thread. Especially when using a bucket... I expect that when you open it you will see that fermentation has started. Another leaky bucket seal....

I still say that leaving the rehydrated yeast so long was not best, but I don't think any real harm can come from that happening.
ding ding ding

The bucket lid and or air lock bung hole were leaking. I opened the bucket and was amazed at the amount of bubbles. hydrometer read 10 points lower than OG so its off to a good start.

Thinking back, maybe the wort was too cool to start as well, so as the wort warmed up the yeast also woke up

I put a blowoff tube on because the airlock w/ starsan solution has made a mess already since resealing 20mins ago

Really happy :)

At least my 3711 starter I can crash cool and make another saison with this week :rockin:
 

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