StMarcos
Well-Known Member
Once the fermentation is vigorous, I doubt very much that inward diffusion could keep up with the CO2 front.
Yeastcalc.com (Now two stir plate options?)
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WoodlandBrew
Well-Known Member
Kai,
Here is another couple of data points:
1) Starting cell count 123 million per ml, 10.2°P wort, 202 million per ml final. (283 estimated)
2) Starting cell count 162 million per ml, 11.3°P wort, 276 million per ml final. (342 estimated)
The first one is Star San washed yeast and the second is the same yeast but not washed. My "laboratory temperature" is currently 60°F which also might have something to do with the lower growth.
Here is another couple of data points:
1) Starting cell count 123 million per ml, 10.2°P wort, 202 million per ml final. (283 estimated)
2) Starting cell count 162 million per ml, 11.3°P wort, 276 million per ml final. (342 estimated)
The first one is Star San washed yeast and the second is the same yeast but not washed. My "laboratory temperature" is currently 60°F which also might have something to do with the lower growth.
WoodlandBrew
Well-Known Member
Cell density of washed yeast is typically 2-4 million per ml. You are probably near 300-600 billion cells. You should have plenty even if the viability is low. You might see muted yeast flavors from over pitching, but that's normally better than under pitching.
Thank you for the response.
Here's how my math went using assumptions pulled from all over the internet:
Assume 4.5 billion cells/ml in washed yeast
Assume 85% is yeast and 15% is trub, so that leaves 3.8 billion/ml
Yeast will be 80 days old when I make the starter, so that is 44% viability (assuming 0.7% loss/day)
That leaves 2 billion cells/ml
and I have ~150 ml, so I have 252 billion cells
I'm making 15 gallons of beer next Saturday; 10 gal of a pale ale where I calculate I need 319 billion cells and 5 gallons of a Breakfast Stout clone where I need 291 billion cells, so I'm hoping to make 1 two step starter with my 150 ml of slurry to get up to the ~600 billion cells needed and then split it for the two batches. How does that sound?
I have the capability to do 2 smaller 1 step starters if you think that is better.
WoodlandBrew
Well-Known Member
That sounds solid to me. Counts I have done on refrigerated slurries indicate that your viability will be much higher than 44%, but other than that I agree.
Two small starters may be optimal here because the entire cell population will be grown faster than with a stepped starter. Your inoculation rate will be plenty high making a low risk of another organism dominating the population. A typical beer is inoculated at about 10 million per ml. Beer is bottle conditioned at 1 million per ml. Assuming 1L of 1.040 (10°P) your starters will be at about 200 million per ml, and should yeild about 300 billion cells.
Thank you very much. Much appreciated.
maida7
Well-Known Member
Fascinating stuff!
I make a starter on a stirplate for every batch. I have used the Mr Malty calculator for several years to determine the size starter I need.
I brew several yeast flavored ales such as Belgian ales and German style wheat's. I have noticed that the resulting beer is fairly clean with muted esters. It's very possible that the Mr. Malty calculator has me over pitching.
I'm gonna try Kai's version for a few brews and see how that effects the flavor.
Thanks to all who are doing the experiments and research. I think it's great stuff and a huge benifit to brewers everywhere. You guys deserve a medal (and free beer). Cheers!
I make a starter on a stirplate for every batch. I have used the Mr Malty calculator for several years to determine the size starter I need.
I brew several yeast flavored ales such as Belgian ales and German style wheat's. I have noticed that the resulting beer is fairly clean with muted esters. It's very possible that the Mr. Malty calculator has me over pitching.
I'm gonna try Kai's version for a few brews and see how that effects the flavor.
Thanks to all who are doing the experiments and research. I think it's great stuff and a huge benifit to brewers everywhere. You guys deserve a medal (and free beer). Cheers!
wow, theres some good reading here. I have always wondered how accurate these calculators could be. one other question, is it just me or did the viability calculator in yeastcalc also change? last week I could have swore that when I entered the date of 10-2012 from my wyeast pack into the calculator it predicted a 1% viability. now it is 30%. WoodlandBrew, how much viability do you think a WL vial or a wyeast smack pack loses over a month, year, etc? just playing with the numbers with yeastcalc, there is such a variation on what I could have pitched into my beer. when I calculated my smack pack of being 1% viable, I started with a .5L starter, then a .75L, then a 1.75L, all on a stir plate, stepping up about every 24hrs. is that bad?
Kaiser
Well-Known Member
Looks like the "no reverse engineering" clause on Mr. Malty is new. I checked with Dustin (who wrote yeastcalc) and he hasn't seen it before.
In that case it doesn't apply to the reverse engineering I already did
Not that I was worried.
Jamil also comments on yeast calculators and how others are "ripping off" his work in the first few minutes of the 12-24-2012 Brew Strong episode.
Kai
In that case it doesn't apply to the reverse engineering I already did
Not that I was worried.
Jamil also comments on yeast calculators and how others are "ripping off" his work in the first few minutes of the 12-24-2012 Brew Strong episode.
Kai
Hermit
fuddle
Like he sat down with the microscope and did all of the yeast counts and research himself over the years?Looks like the "no reverse engineering" clause on Mr. Malty is new. I checked with Dustin (who wrote yeastcalc) and he hasn't seen it before.
In that case it doesn't apply to the reverse engineering I already did
Not that I was worried.
Jamil also comments on yeast calculators and how others are "ripping off" his work in the first few minutes of the 12-24-2012 Brew Strong episode.
Kai
Kaiser
Well-Known Member
I actually don't doubt that he did. It would be unfair to say that he didn't base his calculator on research.
Hermit
fuddle
Taking out the stuff I'll be sorry for later, I'll just say he didn't start completely from scratch and relied on the work of others even if he did sit around and count yeast. I guess it galls me a little having an 'open source' kinda view anyhow and I'll stop before I 'go off' here.
I've noticed the same thing. The first hefeweizen I brewed with no knowledge of proper pitch rates turned out great. The one I brewed last summer was more like an American wheat.maida7 said:
CloverBrew
Well-Known Member
this may be asking a boatload. but I was wondering if there was a possibility of you coming up with some sort of new calculation formula for yeast viability. or a simple way for me to get a reasonable idea of how how the yeast count is in my purchased vials/smack packs.
I read your online results and i am intrigued. I'm in the middle of remodeling my house, and the smack packs I bought for my freezing project are still in my fridge, awaiting propogation. untill further notice. maybe 2 weeks. they have already been in the fridge for 2 weeks. and a couple of the packs were already 2 weeks old when I got them. giving the yeast possibly 6+ weeks of waiting
I ask this because i've been using yeast calc, mr. malty, and brewers friend to get yest viability estimates for my yeast project. i'm building yeast colonies for freezing. i just wanted to be able to use your method to estimate cell count in my cultures. thanks in advance
WoodlandBrew
Well-Known Member
Viability doesn't seem to drop much but glycogen reserves are likely depleated in refriderate slurries. I've used slurries that have been in the fridge for a month and in one case it actualy outpreformed the same yeast taken at high kaurosen.
http://woodlandbrew.blogspot.com/2013/03/side-by-side-starters-4-of-4.html
Freezing the yeast in the condition it is in should be fine, but I imagine it will last even longer if you grow it up two or three fold before freezing. (Make sure to let the fermentation run to completion so rebuild the glycogen, and crash it in the fridge.)
But as for an equation to estimate viability based on date I don't have one. I've been meaning to count viability on my old slurries again to see how they compare to the data from 3 months ago. (Perhaps this weekend)
The biggest direct impact to viability I have seen is ABV:
http://woodlandbrew.blogspot.com/2013/01/abv-effects-on-yeast.html
A better indication of health is glycogen and pH over time rather than viability. This is something I would like to do, but don't have good tools for the testing.
simonbones
Member
I've been playing with my microscope and methylene blue for the last couple months doing 48hr starters on my Black Maxx. I have generally found the Zainesheff stir plate method to be more accurate to my numbers.
Example: I pitched one vial of wlp510 into 1800mL of 1.040 wort. According to yeastcalc and the vial date, I pitched with 66% viability, though I did not verify this time with initial count/viability.
After 48hrs, I counted 264.6 billion cells at 90.48% viability leaving me 239.41 billion viable cells.
Zainesheff stir plate method predicted I would have 238 billion cells. Troester predicted 319 billion.
This has held fairly consistent for all my starters, Troester tends to overshoot. All starters were into 1500-4000mL volumes with 1-2 vials at 76F. I suppose accuracies could be different by changing variables like temp, water chem profile, or perhaps scaling. YMMV.
Given my current viability, I have approximately 25.19 billion dead cells in there. Assuming most of those were there in the start, I would have started with ~75% viability at the beginning.
Example: I pitched one vial of wlp510 into 1800mL of 1.040 wort. According to yeastcalc and the vial date, I pitched with 66% viability, though I did not verify this time with initial count/viability.
After 48hrs, I counted 264.6 billion cells at 90.48% viability leaving me 239.41 billion viable cells.
Zainesheff stir plate method predicted I would have 238 billion cells. Troester predicted 319 billion.
This has held fairly consistent for all my starters, Troester tends to overshoot. All starters were into 1500-4000mL volumes with 1-2 vials at 76F. I suppose accuracies could be different by changing variables like temp, water chem profile, or perhaps scaling. YMMV.
Given my current viability, I have approximately 25.19 billion dead cells in there. Assuming most of those were there in the start, I would have started with ~75% viability at the beginning.
Hermit
fuddle
How vigorously do you stir the yeast? I've been wondering about this one for awhile now. Once I get krausen on my starter I wonder if I really get anymore oxygenation going on. My plate throws the bar at high speeds so I just get the 'dimple'. Do people pulling vortexes prevent krausen and get oxygenation throughout the process and therefore get more division?
CyclingCraig
Well-Known Member
I noticed the same thing? I think it Definitely changed.
I just made a starter, and when I pluged in my numbers for a yeast production date of Feb 13, 2013. YeastCalc has Viability at 69% and MrMalty has it at 47%.
I *THOUGHT* they used to match up?
-Craig
maida7
Well-Known Member
Fascinating!
theveganbrewer
Well-Known Member
Just my uneducated opinion using both these methods. I think the Troester are always high, and Jamil's are usually within 5-10%. It seems like Troester would be correct in perfect world scenario, in theory, but not reality.
Hermit
fuddle
I'm pretty sure Kai's numbers are based on his own research. His methods are published and documented. Can you point me to Jamil's research and his explanation on how he arrived at his numbers?
jwalker1140
Well-Known Member
Check out the Brew Strong podcasts on starters and washing. I know he talks about it there, in addition to plenty of other Brewing Network podcast episodes. I've heard him say multiple times that he counted the cells himself from his own beers and I also remember a conversation he had with Chris White where they discussed the research they each did.
Sure, we all stand on the shoulders of others to some degree, but I don't have any reason to doubt that he personally recorded the data points that were fed into the Mr. Malty calculator.
theveganbrewer
Well-Known Member
Aren't they in his yeast book? I haven't read it in a while but I thought there was some talk on this topic in the book.
Hermit
fuddle
There is some but the book is Chris White "with" Jamil Zainasheff so I always took that to mean it was basically CW with JZ playing the role of a ghost writer.
maida7
Well-Known Member
well they both can't be right... Can they?
simonbones
Member
I've wondered the same thing. My Black Maxx can get an awesome vortex that can diffuse air bubbles through the starter. But sometimes I'll get a krausen and other times I won't. When I do, it can go bananas and want to foam out of the top. I can't help but wonder if getting a high krausen foaming up will block the O2 exposure and give a lower growth rate. Perhaps I should start experimenting with giving a pure O2 burst first?
The variation could be in the details that we don't know: yeast strain, temp, yeast health, nutrient, type of stir plate etc.
Sorry if this is off topic:
I'm concerned about the difference in the viability calculator. My HBS has a lot of yeast in the second half of its life span and the difference in yeast viability is significant. I read the work by Woodland and Kai, and I think both made starters from stored yeast... and that might be different from vials or smack packs. Idk.
Sorry if this is off topic:
I'm concerned about the difference in the viability calculator. My HBS has a lot of yeast in the second half of its life span and the difference in yeast viability is significant. I read the work by Woodland and Kai, and I think both made starters from stored yeast... and that might be different from vials or smack packs. Idk.
