Author Topic: Reusing lager yeast  (Read 4885 times)

Offline 1vertical

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Re: Reusing lager yeast
« Reply #15 on: February 24, 2011, 10:37:41 AM »
I just re-used some S-189 and the thing is that on the second usage, I forgot to add
the yeast nutrient to the BK.  I pitched the cooled wert onto the 1 inch of slurry that
was left in the fermenter after 2 weeks of sitting in the cold 40 deg f garage. Fermentation
took off nicely with a 24 hour lag from start.  The beer was at O.G. 1.050 and the F.G.
was only 1.018 so it did not really attenuate well...The 1st beer seemed to attenuate
much better with O.G 1.060 and F.G. 1.014.  I prolly would have gotten better results
had I not forgotten to add the nutrients.  Livin...learnin  :P
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Offline denny

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Re: Reusing lager yeast
« Reply #16 on: February 24, 2011, 11:01:04 AM »
Even though I use nutrient myself, I'm not sure I'd attribute the poorer attenuation to not using it.
Life begins at 60.....1.060, that is!

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Offline 1vertical

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Re: Reusing lager yeast
« Reply #17 on: February 24, 2011, 11:50:21 AM »
If that is the case Denny, I am wondering what in the heck did cause the difference.
I pitched a lower gravity wert onto a Massive yeast slurry. I pampered that yeast
kept it cool...in the dark in the bottom of the bucket blanketed in CO2.  Fermented
it well within the parameters and gave it a week and a half at warmer temps to finish
prolly was around 60-62 ish for the long d-rest.  It tastes a bit sweet not cloying, but
sweetish. ???

And Oxygen, yep I shoot the ox to it with the ability to use medical tank and a couple
of minutes of fine 2 micron mesh bubbles....LOTS of oxygen.
« Last Edit: February 24, 2011, 12:04:07 PM by 1vertical »
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Offline Kaiser

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Re: Reusing lager yeast
« Reply #18 on: February 24, 2011, 07:06:29 PM »
could it be that the yeast sat dormant for too long?

Kai

Offline 1vertical

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Re: Reusing lager yeast
« Reply #19 on: February 24, 2011, 10:48:54 PM »
could it be that the yeast sat dormant for too long?

Kai
Kai, I cannot rule that possibility out since I did no testing fast ferment or anything.
It was sitting about a week and a half.  I thought It would just have been the
equivalent of a huge starter but not sure. It just had enough. Consequently, instead
of brewing with that again, I will start with fresh yeast It must be stressed somehow.
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Offline blatz

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Re: Reusing lager yeast
« Reply #20 on: February 25, 2011, 08:10:56 AM »
could it be that the yeast sat dormant for too long?

Kai

I go back and forth on this a lot - recently, I pitched a helles with yeast that sat in a jar for 3 weeks since racking pils off the top and collecting.  I pitched about 50% more than mrmalty.com recommended and although it took about 36-48 hours to show airlock activity, it fell from 1.050 to 1.012 in less than 2 weeks.  I did not have a chance to do FFT on this one.

point is, sometimes it seems extended dormancy is a major factor, other times its irrelevant.

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Offline Kaiser

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Re: Reusing lager yeast
« Reply #21 on: February 25, 2011, 08:32:27 AM »
Quote from: blatz link=topic=5994.msg73461#msg73461 date=1298646656
point is, sometimes it seems extended dormancy is a major factor, other times its irrelevant.
[/quote

I agree that this is a subject that may warrant more investigation. In the end it is not just about how fast and how well the beer attenuates but it is also important how the final product tastes. My recommendations are largely based on what I have observed. Records of measured values, like gravity and attenuation, are always better than recollection of taste.

Kai

Offline kcjaz

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Re: Reusing lager yeast
« Reply #22 on: February 25, 2011, 10:44:19 PM »
Now they seem to both be going at about the same rate.  I'll rack to secondary on Friday and take a gravity reading and taste test.  So far though, I don't see any ill affect from my old yeast.  The proof though will be in the gravity numbers and the taste.

OK, its Friday now and I racked both carboys to secondary carboys, 6.5 days after pitching (I pitched the yeast last Saturday morning). Gravity data is this:

Old yeast:1.014
New yeast: 1.013

Both were in the same fridge held at 50F.  While it's tempting to say the new yeast did better, I'd say 0.001 difference in gravity after 6.5 days is really, in practical terms, pretty much the same.  The taste between the two was very similar.  I'd say the old yeast was a tad sweater but I think that is just because I knew the gravity was higher.  In a blind test, I don't think I could tell the difference.  There was nothing funky with the old yeast.  Now I'll drop the temp a couple degrees each day down to 36 or so and lager until the gravity levels out.  This is a new recipe so I'm not sure where it will end up but I'm hoping for 1.008 or so.  I'll post the final results when I have then.
Jason Zoller

Offline johnf

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Re: Reusing lager yeast
« Reply #23 on: February 26, 2011, 11:01:37 AM »
Aren't the vials and smack packs we buy similar to the harvested yeast we store in the fridge?  They're just sitting there in the LHBS fridge.   Are they not becoming less viable with time in the same manner as our home harvested?

I think the conditions in the white labs or wyeast package are a bit more optimal but yes it is similar to stored slurry. That's one reason I wouldn't ask these companies to package large quantities of yeast. If I can't get it within a couple of days (I sometimes can but I cannot count on that) I would want to use a smaller quantity and a starter anyway.

Offline kcjaz

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Re: Reusing lager yeast - Update
« Reply #24 on: March 21, 2011, 06:41:40 PM »
OK, here are the final numbers.  To remind everybody, on February 18, I brewed an 11 gal batch of wheat beer.  OG = 1.044.  I had some old yeast slurry saved from a previous lager batch that was brewed on Thanksgiving (Wyeast 2035).  I had periodically been "feeding" this yeast with shots of DME wort.  On brewday, I took this old yeast and made a new starter from a 1/2 gal of my new wheat beer.  I also did the same thing with a brand new smack pack of 2035.  I let the starters do their thing over night while I let the remaining 10 gal of wort chill and settle in the fridge.  The next morning, I racked the work of the trub into new carboys and pitched each starter into the wort at 50F.

Both took off pretty quickly. 7 days later on 2/25 the gravities were:

New yeast = 1.013
Old yeast  = 1.014

Today (3/21/2011), after lagering at 33F since 2/25 the gravities are:

New yeast = 1.010-
Old yeast  = 1.010

I put the minus sign after the 1.010 for the new yeast because it was a slightly lower reading than the 1.010 for the old yeast. 

I can't say that I can detect any real flavor difference between the two half batches.  The "old yeast" may be a little sweater but it is barely perceptible, I may even be imagining it.  Both taste really good.  I am certain that any taste difference could only be noticed by tasting each beer side by side.  Tasted months apart, with different batches, you could never tell, there are many more other factors that could cause "identical" homebrew batches to be different (that is part of the fun). 

My conclusion is that the "old yeast" was just fine to use and conversley, the "new yeast" provided no real advantage in the end product.  The only advantage I see for the "new yeast" would be a higher chance of success and and lower chance of something bad happening. 
Jason Zoller