Author Topic: Reusing yeast, high gravity to low gravity  (Read 520 times)

Offline mdyer909

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Reusing yeast, high gravity to low gravity
« on: December 20, 2018, 09:59:29 PM »
I’ve successfully reused yeast starting with lower gravity beers to higher ones, e.g. bitter to barley wine;  wit to a triple.  I’ve got a bock that’s ready to come off the yeast and would like to use the yeast again to brew a pils or Vienna lager.  The wisdom I’ve gleaned from the literature would advise against it, but wondering if it matters a great deal in practice.  The OG of the bock was 1070.  Yeast was Wyeast Bavarian lager.

Offline denny

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Re: Reusing yeast, high gravity to low gravity
« Reply #1 on: December 20, 2018, 10:59:09 PM »
1.070 is about my limit for reusing, so I say no problem
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Offline a10t2

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Re: Reusing yeast, high gravity to low gravity
« Reply #2 on: December 20, 2018, 11:00:07 PM »
I'd up the pitching rate slightly, but like Denny says, that isn't high enough gravity to expect any problems.
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Offline Robert

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Re: Reusing yeast, high gravity to low gravity
« Reply #3 on: December 21, 2018, 02:17:42 AM »
As a rule, I'd ask the same question no matter the gravity:  Did the yeast perform as expected in the last batch?  Reach expected FG in the expected time, taste right, normal pH, normal flocculation, etc. etc.?  If so, it's in good shape to go back to work.  If there's ever any hint of abnormal performance,  don't reuse the yeast.

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Offline ynotbrusum

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Re: Reusing yeast, high gravity to low gravity
« Reply #4 on: December 21, 2018, 12:30:22 PM »
Be sure to give it some yeast nutrient (zinc based) and you will be good to go repitching recent slurry, if it was harvested awhile back, then I’d consider a vitality starter.
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Offline spurviance

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Re: Reusing yeast, high gravity to low gravity
« Reply #5 on: February 05, 2019, 05:10:52 PM »
1.070 is about my limit for reusing, so I say no problem
After some exhaustive internet searches (15 min at least) I'm finding that this seems to be the conventional wisdom.  The one Brulosophy experiment seems to validate this with a slightly different aroma from 'overstressed' yeast reused from a high OG batch.  http://brulosophy.com/2018/05/28/fresh-yeast-vs-slurry-harvested-from-a-high-og-beer-exbeeriment-results/.  What side effects have you seen from reusing high OG yeast that you have come up with your limit?  I have a 3rd generation Imperial Harvest yeast kicking butt on a 1.090 Dopplebock right now that I was considering for a Vienna lager, but now thinking I'm better off forking out the $$ for fresh yeast.
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Offline mdyer909

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Re: Reusing yeast, high gravity to low gravity
« Reply #6 on: February 19, 2019, 10:29:22 PM »
So I did repitch the yeast from the bock I brewed back in December into a pils yesterday, and it’s fermenting away nicely.  After I racked the bock into a secondary I poured the yeast cake into a sanitized mason jar covered with about three inches of beer, and put it down in the cellar with the pickles and sauerkraut.  It’s a dank dark place dug in the 1890’s, but it stays just around 32f this time of year.  I brought it upstairs this weekend and proofed out a sample by putting about a half teaspoon of the cake in some water with a pinch of sugar like you’d do with bread yeast.  Bubbled right up.

I poured the old beer off the rest of the cake, boiled and cooled 5 teaspoons of Fermax yeast nutrient with some water and poured that into the jar with the yeast,  gave it a swish and then pitched that into the pils.  I ferment in the attic and it’s about 44f up there now.