Author Topic: Harvested Yeast - what is going on?  (Read 398 times)

Offline blatz

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Harvested Yeast - what is going on?
« on: April 12, 2018, 07:07:07 PM »
Noticed this many times over the years, but never really thought much of it until now.

sometimes, when I keep a harvested slurry in a mason jar, initially the slurry separates from the wort and the wort drops bright.  Then after a few weeks, the wort clouds up again.  any insight into what might be happening?
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Offline klickitat jim

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Re: Harvested Yeast - what is going on?
« Reply #1 on: April 12, 2018, 09:27:47 PM »
Only guesses. Sounds like either autolysis or contaminants.

Offline Robert

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Re: Harvested Yeast - what is going on?
« Reply #2 on: April 12, 2018, 10:02:12 PM »
Also just guesses.  But could it be either (not necessarily autolysis but) dead cells floating up into the liquid, or the slow release of CO2 as metabolism slowly continues carrying material up?
Rob
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Offline klickitat jim

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Re: Harvested Yeast - what is going on?
« Reply #3 on: April 12, 2018, 10:52:56 PM »
I always assume that haze that appears when it shouldn't is contamination. I'm not saying that's always what it is, but since I don't have a microscope or staining, I can only guess. I doubt that protein got in there, or new hop polyphenols, so if I assume it's a contamination my reaction will cover anything else it might be. Dump, thorough cleaning, thorough sanitation... maybe even sterilization if it's parts that would survive my autoclave (pressure cooker).

Offline blatz

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Re: Harvested Yeast - what is going on?
« Reply #4 on: April 13, 2018, 02:13:07 PM »
I doubt its contamination.  I see this in probably 3 of every 4 slurries that I keep over a month (which is usually the ones that I think i'll use in the future but don't).  If it was contamination I would expect that would suggest something in my normal brewing, and in ~250 batches, I've had less than a handful that got contaminated.

I was thinking the autolysis issue as well.  its 4 weeks old, and it went from crystal clear to cloudy right at the end of week 4.

I did plan on pitching this slurry into a starter in 2 weeks and using it again.  wondering if I should thinking about rinsing it or something.
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Offline Robert

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Re: Harvested Yeast - what is going on?
« Reply #5 on: April 13, 2018, 02:28:06 PM »
I used to be a yeast rinser.  Denny isists it has no benefit, and I tend now to agree.  Especially as Jim keeps pointing out:  dead stuff and trub won't propagate! If there's no contamination, I'd just pitch it to a starter, which will grow the live stuff to the maximum potential count given the density and volume of the starter wort.
Rob
Akron, Ohio

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Offline blatz

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Re: Harvested Yeast - what is going on?
« Reply #6 on: April 13, 2018, 02:55:55 PM »
I used to be a yeast rinser.  Denny isists it has no benefit, and I tend now to agree.  Especially as Jim keeps pointing out:  dead stuff and trub won't propagate! If there's no contamination, I'd just pitch it to a starter, which will grow the live stuff to the maximum potential count given the density and volume of the starter wort.

yeah ive never been a rinser;  I tried it once about 10 years ago and decided it was too much work for little appreciable benefit.  good points.   
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Offline Robert

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Re: Harvested Yeast - what is going on?
« Reply #7 on: April 13, 2018, 07:53:25 PM »
I also generally repitch directly, no starter.  But if there's any doubt about the yeast, a starter will provide one last chance to spot any off aroma or odd behavior. 
Rob
Akron, Ohio

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Offline blatz

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Re: Harvested Yeast - what is going on?
« Reply #8 on: April 13, 2018, 07:55:30 PM »
I also generally repitch directly, no starter. 

same here, but im usually repitching within 2, maybe 3 weeks at most.  in this case I'm going to be approaching 7 weeks and I feel I'll need to kickstart it.
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Offline majorvices

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Re: Harvested Yeast - what is going on?
« Reply #9 on: April 15, 2018, 12:38:01 PM »
Maybe its just dead yeast, and yes I've seen the same thing.

Get you a microscope, a hemocytometer and some methylene blue and find out. ;)

Offline hawkbox

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Re: Harvested Yeast - what is going on?
« Reply #10 on: April 16, 2018, 01:45:33 AM »
I save part of the starter for the next batch, and I don't have any issues.  I wouldn't worry to much about it if you don't have any issues.