I noticed a change in the options on yeastcalc.com. There are now 2 stir plate options, one with J. Zainesheff in parenthesis, one with K. Troester. The Troester numbers seem more optimistic (higher cell count) by about 15%. Does anyone know the difference?
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el_caro
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My limited experience with using Kai Troester setting confirmed the growth rate projected by the calculator.
There is not that big a difference between the two stir plate settings when pitching a larger quantity of yeast ( a higher pitch rate).
For example 100bn cells into 1L starter will get you 236bn with KT and 222bn with JZ. Not a huge difference.
But should you pitch only 5bn cells into 1L starter JZ will only estimate 43bn while KT calculates 144bn. One hell of a difference and my experience suggests KT is correct.
The problem is that if you use such a low pitch rate you will likely produce a significant number of unhealthy yeast cells.
Just my 0.02cents worth.
There is not that big a difference between the two stir plate settings when pitching a larger quantity of yeast ( a higher pitch rate).
For example 100bn cells into 1L starter will get you 236bn with KT and 222bn with JZ. Not a huge difference.
But should you pitch only 5bn cells into 1L starter JZ will only estimate 43bn while KT calculates 144bn. One hell of a difference and my experience suggests KT is correct.
The problem is that if you use such a low pitch rate you will likely produce a significant number of unhealthy yeast cells.
Just my 0.02cents worth.
benbradford
Well-Known Member
I find the differences to be pretty dramatic at larger samples...
For example 71bn cells into 5L starter will get you 776bn with KT and 395bn with JZ. Pretty big difference.
I am planning a 15 gallon brew at 1.050. With KT I can use a 3.25L starter but JZ requires a 9.4L starter. Even splitting the difference is a large starter of 6.325L starter.
Pretty bummed out because after reading Chris White's book Yeast, I was under the impression that I would be able to propogate yeast with factual information versus conjecture.
What processes and formulas do major breweries use?
Does this indicate that I am left with the idea of buying a microscope and starting to count my own cultures.
For example 71bn cells into 5L starter will get you 776bn with KT and 395bn with JZ. Pretty big difference.
I am planning a 15 gallon brew at 1.050. With KT I can use a 3.25L starter but JZ requires a 9.4L starter. Even splitting the difference is a large starter of 6.325L starter.
Pretty bummed out because after reading Chris White's book Yeast, I was under the impression that I would be able to propogate yeast with factual information versus conjecture.
What processes and formulas do major breweries use?
Does this indicate that I am left with the idea of buying a microscope and starting to count my own cultures.
Warthaug
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mtnagel linked you to the relevant info.
Long story short, the White/Zainasheff numbers are based on extrapolation from non-stirred starters, based on some assumptions of how yeast behave based on cell density and oxygen availability. The Troester numbers are based on actual observations of yeast growth in stirred starters.
If using a stirplate, use the Troester setting.
Bryan
Long story short, the White/Zainasheff numbers are based on extrapolation from non-stirred starters, based on some assumptions of how yeast behave based on cell density and oxygen availability. The Troester numbers are based on actual observations of yeast growth in stirred starters.
If using a stirplate, use the Troester setting.
Bryan
benbradford
Well-Known Member
oops, I read that thread also and actually thought that I was posting on that thread.
No commentary on either thread for 5 months, and I was curious if more research was being conducted.
No commentary on either thread for 5 months, and I was curious if more research was being conducted.
Yeastcalc.com is gone! the domain has not been renewed! Nooooooooooooooo.............
NervousDad
BFM
Thanks! I was worried for a second.
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