Author Topic: Yeast Viability Question  (Read 505 times)

Offline goose

  • Assistant Brewer
  • ***
  • Posts: 223
    • View Profile
Yeast Viability Question
« on: December 17, 2018, 03:57:12 PM »
I have been using the yeast calculator in BeerSmith to calculate my liquid yeast starter sizes for a while now since I can easily keep track of all the information for each brew in my brewery computer.  Although it is a bit less conservative than Jamil's Mr. Malty calculator (which I have used in the past), it appears to work well for me with regard to short lag times and no apparent fermentation issues.

One thing that I have noticed is that I see a difference in the viability numbers between Wyeast smack packs and White Labs Pure Pitch packs.  I usually try to get the freshest yeast I can from my LHBS but when it comes to making starters but there was a pretty big difference in the amount of yeast I need each starter.  For example, I recently brewed a Wee Heavy and the BeerSmith calculator told me that I needed two smack packs of 1028 for a 10 gallon batch to get the proper number of cells.  The yeast was only one month out from the production date.  I made a 3 liter starter with one pack and according to the calculator I under-pitched by about 40%.  I used the RDWHAHB approach here so I didn't have to drive 30 miles to get another pack of yeast.   The beer took off without an excessively long lag time and I tasted no off flavors from stressing the yeast.
Yesterday I brewed a 10 gallon batch of ESB (more properly called a Strong Bitter) using one pack of White Labs WLP-002 again one month out from the production date.  The calculator told me that one pack and a 2.5 liter starter was sufficient.  Note that this was slightly under-pitched but if I get the starter within 10 to 20 billion cells, I roll with it because I am within 10% of the calculator.  Again, RDWHAHB.   The lag time for this beer was the same as the Wee Heavy.

The BeerSmith calculator told me that the 1028 had only about 68% viability while the WLP-002 had roughly 82% viability.  That seems a bit strange for two yeasts there were used in the same time frame away from their production dates.  I am wondering if anyone else on this forum has experienced this issue.  I know that yeast calculators are approximate but the "cells needed" count from both Mr. Malty and BeerSmith were in  good agreement for both strains.

Now I am well aware that differences in starting gravities effect the size of the starters and the strains have different characteristics which play into the equation, but the OG's of these two beers were not that far apart.  I am just curious as to why one starter required twice as much yeast as the other.  Is the viability of White Labs yeast better than Wyeast?  I like them both and will continue to use both.
Goose Steingass
Wooster, OH
Society of Akron Area Zymurgists (SAAZ)
Wayne County Brew Club
Mansfield Brew Club
BJCP Certified
AHA Governing Committee Member

Offline denny

  • Administrator
  • Retired with too much time on my hands
  • *****
  • Posts: 20240
  • Noti OR [1991.4, 287.6deg] AR
    • View Profile
    • Dennybrew
Re: Yeast Viability Question
« Reply #1 on: December 17, 2018, 04:09:38 PM »
Could it be that yeast calculators don't really know?  I keep thinking of what Chris White said to me that homebrewers are too hung up on numbers.  I truly believe that.  In the years since I stopped using yeast calculators and stir plates, my beer quality hasn't changed.  What has changed is the amount of hassle I go through.
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3537
  • Two Rivers, WI
    • View Profile
    • Manty Malters - Meet the Malters! - Dave Taylor
Re: Yeast Viability Question
« Reply #2 on: December 17, 2018, 04:26:11 PM »
Could it be that yeast calculators don't really know?  I keep thinking of what Chris White said to me that homebrewers are too hung up on numbers.  I truly believe that.  In the years since I stopped using yeast calculators and stir plates, my beer quality hasn't changed.  What has changed is the amount of hassle I go through.

This ^^^^.  So very much, this!

We all need to stop worshipping pseudo-science that has unknown (and perhaps non-existent?!) basis, and just do whatever it is that we ourselves know from experience that works.

Personally I find that my beers turn out good using about 1/2 of whatever MrMalty calculates.  I'm not familiar with the BeerSmith tool but it sounds to be in the same boat.  I think viability of properly stored yeast is WAAAAAAY better than any of the tools predict.  68% and 82% for one-month-old yeast....... yeah.... somehow I just cannot accept that, it doesn't make much sense, not to me anyway.  If it were mishandled, okay then.  But we generally treat our yeast pretty nice, right?!

Here's another wrench to throw into the machine:  We used to have a guy on this forum who went by the name of S. cerevisiae who was a reknowned expert on yeast.  I think he still shows up from time to time.  Not too long ago he said that cell counts are essentially bunk, and what's much more important is the mass of yeast cells.  Not the cell count, because cells are all different sizes.  It's really the mass (or was it volume?) that matters most of all.  Somebody with more gumption than I might provide the link for you, or run a search on it.  I believe Denny was advocating for this at one time as well.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline Robert

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2897
    • View Profile
Re: Yeast Viability Question
« Reply #3 on: December 17, 2018, 04:54:36 PM »
^^^^
All of this, and:
I also remember that Mark (S. cerevisiae) somewhere detailed the effects of different pitch rates, i.e. "underpitching,"  as long as those cells are healthy.  It worked out that half the cell count only resulted in something like an extra 60-90 minutes of lag time (as the cells grow to the same final count) or something like that.  No other adverse  effects.  It'd be well worth a search to find his posts on all of this.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

Offline mainebrewer

  • Brewer
  • ****
  • Posts: 459
  • Palermo, Maine
    • View Profile
Re: Yeast Viability Question
« Reply #4 on: December 17, 2018, 05:11:26 PM »
To paraphrase one of Mark V's comments: the amount of yeast that is pitched is like horseshoes - close enough is good enough.
BJCP Certified

Offline metron-brewer

  • Assistant Brewer
  • ***
  • Posts: 163
  • White Bear Lake, MN
    • View Profile
Re: Yeast Viability Question
« Reply #5 on: December 17, 2018, 05:50:47 PM »
"Yeast Cultures Are Like Nuclear Weapons"

[urlhttps://www.experimentalbrew.com/blogs/saccharomyces/yeast-cultures-are-nuclear-weapons][/url]

Ron B.
White Bear Lake, MN

Offline kramerog

  • Senior Brewmaster
  • ******
  • Posts: 1903
    • View Profile
    • My LinkedIn page
Re: Yeast Viability Question
« Reply #6 on: December 17, 2018, 06:39:50 PM »
Here's another wrench to throw into the machine:  We used to have a guy on this forum who went by the name of S. cerevisiae who was a reknowned expert on yeast.  I think he still shows up from time to time.  Not too long ago he said that cell counts are essentially bunk, and what's much more important is the mass of yeast cells.  Not the cell count, because cells are all different sizes.  It's really the mass (or was it volume?) that matters most of all.  Somebody with more gumption than I might provide the link for you, or run a search on it.  I believe Denny was advocating for this at one time as well.

I think what DM referring too is based on statements made by Omega Labs.  So it turns out that beer yeast can have very different sizes - saison yeast is about a 1/5th the size of typical ale yeast.  Ultimately it doesn't matter; yeast calculators do a good enough job because the mass of yeast comes out to be about right even when the yeast are abnormally small.

Oh, here's the link https://www.homebrewersassociation.org/forum/index.php?topic=32084.0.

Offline goose

  • Assistant Brewer
  • ***
  • Posts: 223
    • View Profile
Re: Yeast Viability Question
« Reply #7 on: December 17, 2018, 07:10:12 PM »
Could it be that yeast calculators don't really know?  I keep thinking of what Chris White said to me that homebrewers are too hung up on numbers.  I truly believe that.  In the years since I stopped using yeast calculators and stir plates, my beer quality hasn't changed.  What has changed is the amount of hassle I go through.

This ^^^^.  So very much, this!

We all need to stop worshipping pseudo-science that has unknown (and perhaps non-existent?!) basis, and just do whatever it is that we ourselves know from experience that works.

Personally I find that my beers turn out good using about 1/2 of whatever MrMalty calculates.  I'm not familiar with the BeerSmith tool but it sounds to be in the same boat.  I think viability of properly stored yeast is WAAAAAAY better than any of the tools predict.  68% and 82% for one-month-old yeast....... yeah.... somehow I just cannot accept that, it doesn't make much sense, not to me anyway.  If it were mishandled, okay then.  But we generally treat our yeast pretty nice, right?!

Here's another wrench to throw into the machine:  We used to have a guy on this forum who went by the name of S. cerevisiae who was a reknowned expert on yeast.  I think he still shows up from time to time.  Not too long ago he said that cell counts are essentially bunk, and what's much more important is the mass of yeast cells.  Not the cell count, because cells are all different sizes.  It's really the mass (or was it volume?) that matters most of all.  Somebody with more gumption than I might provide the link for you, or run a search on it.  I believe Denny was advocating for this at one time as well.

To add to you comment on cell counting, Dave,  I used to do cell counts at the brewery I worked for.  What we did in the lab was to ascertain the mass and viability of the yeast we were re-pitching (I know that this is immaterial for first pitch scenarios).  I would count the live and dead cell and determine viability while at the same time calculating how much yeast mass we needed to pull for a re-pitch.  So there is some validity to cell counts, but your point is well taken.

Denny's no hassle point is also well taken.  I guess my anal retentive gene kicks in when I brew which was the original reason for the post..

I guess to summarize all of the comments here, RDWHAHB!!!  Thanks for the replies.
Goose Steingass
Wooster, OH
Society of Akron Area Zymurgists (SAAZ)
Wayne County Brew Club
Mansfield Brew Club
BJCP Certified
AHA Governing Committee Member

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3537
  • Two Rivers, WI
    • View Profile
    • Manty Malters - Meet the Malters! - Dave Taylor
Re: Yeast Viability Question
« Reply #8 on: December 17, 2018, 07:38:25 PM »
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline Richard

  • Assistant Brewer
  • ***
  • Posts: 209
    • View Profile
Re: Yeast Viability Question
« Reply #9 on: December 17, 2018, 07:43:21 PM »
Getting back to your original question about the aging rate and viability, I also questioned the difference between White Labs and others, but I saw that Brad Smith says that White Labs yeast ages more slowly than other yeasts (because of their packaging), and BeerSmith reflects that slower aging rate. He claims this is based on measurements from White Labs.

http://www.beersmith.com/forum/index.php/topic,16893.msg63846.html#msg63846
Original Gravity - that would be Newton's

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3537
  • Two Rivers, WI
    • View Profile
    • Manty Malters - Meet the Malters! - Dave Taylor
Re: Yeast Viability Question
« Reply #10 on: December 17, 2018, 07:53:31 PM »
Getting back to your original question about the aging rate and viability, I also questioned the difference between White Labs and others, but I saw that Brad Smith says that White Labs yeast ages more slowly than other yeasts (because of their packaging), and BeerSmith reflects that slower aging rate. He claims this is based on measurements from White Labs.

http://www.beersmith.com/forum/index.php/topic,16893.msg63846.html#msg63846

Wow.  That seems really.... questionable.  But fascinating if true.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline mabrungard

  • Brewmaster General
  • *******
  • Posts: 2556
  • Water matters!
    • View Profile
    • Bru'n Water
Re: Yeast Viability Question
« Reply #11 on: December 18, 2018, 02:24:06 AM »
The other factor that throws cell count out the window, is that differing yeast variants have different cell diameters. It appears that the volume of yeast slurry is a decent way to gauge your pitching. Something like 10 ml of compact yeast slurry per gallon of wort is about the right rate for ales.

Remember the old White Labs vials? They probably held something like 50 ml of yeast slurry. That is fitting for a 5 gal batch.
Martin B
Carmel, IN

BJCP National
Foam Blowers of Indiana (FBI)

Brewing Water Information at:
https://sites.google.com/site/brunwater/

Like Bru'n Water on Facebook
https://www.facebook.com/Brun-Water-464551136933908/?ref=bookmarks

Offline Robert

  • I spend way too much time on the AHA forum
  • ********
  • Posts: 2897
    • View Profile
Re: Yeast Viability Question
« Reply #12 on: December 18, 2018, 02:45:51 AM »
In his book, Chris White said that the vials held 47 mL with an average fill level of 36 mL, and that when the yeast settled to the bottom it occupied a space of about 14 mL.  Fully dispersed, cell density would be about 3B/mL, and packed, 8B/mL, he said.  So volume of slurry is going to be a fairly arbitrary way of estimating cell count or mass, to whatever extent that is really needed,  as estimating the density by eyeball is going to be something of a guess.  If you develop a consistent,  repeatable procedure that works for you, quantifying it is unnecessary.  Results are the best guide.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.