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Yeast Cells with Starter Calculation Mismatched after upgrade

BrewMonster111

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I noticed that if i input the yeast starter size that BeerSmith 2.3.6 Recommends, then I fall SHORT of the needed number of cells. 

It doesn't seem to matter if I say I'm using a stir plate or not.  The recommended size is short by 4-6 Billion Cells.  I don't recall this issue with the previous version. 

I have upped the Ale Pitch Rate and reduced the liquid viability percentage, but the Stir Plate Factor, starter Growth Limit and other Yeast Options are set to the defaults. 

What is happening here?
 

Toy4Rick

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Did you set the Pkg Date as noted by the Mfg?  That will affect your total yeast count

Rick
 

BeerSmith

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Check the new age rate on the yeast itself as well.  With the new pure-pitch packages I had to set an age rate for each yeast and its now part of the yeast record itself.  It represents the viability loss each month due to aging.

Brad
 

BrewMonster111

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Those really shouldn't matter, right?  If I start with 100 Billion cells or 65 Billion cells, then a calculator should then take whatever that number is and calculate the recommended starter size based on growth rate, wort gravity, etc.

What I am saying is that when I follow BeerSmith's advice for it's recommended starter size, which I assume has to due with the yeast cells started with and what I need to grow, and ultimately end up with, that BeerSmith's number is TOO SMALL to hit the amount of yeast that BeerSmith Recommends.

If BeerSmith says I need 219.3 Billion cells and a.92 liter starter, then when I change my starter size to .92 L, it should show that I will not have 219.3 million cells, not 212.4 billion, or some other number, right?

I have attached a snip of a screen shot.

What am I missing here? 
 

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  • BeerSmith Yeast.JPG
    BeerSmith Yeast.JPG
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Oginme

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Yes, the date does matter.  Your yeast package date is after your brew date.  Reset it to the actual date on the yeast package.
 

joeinma

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I have noticed the same issue.  For example, I put a recipe in dated today and put the yeast pack date as of today too (just for this example), BeerSmith says I need 217.7 B cells  and a 0.85 Liter starter.  I go below, check off stir plate, put in a 0.85 liter starter, and it calculates that I will only have 210.3 B cells...7.4 billion short.    Have tried changing the gravity of the starter, but that does nothing.
 

BrewMonster111

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Exactly, joeinma.  
Yeast package dates don't matter from a perspective of calculating a known # of cells to a needed # of cells. 
Yes, I would have more cells to start with (theoretically) if using the "correct date" from the yeast package, but the Calculator would still come up short. 
Regardless of starting cell count, the Starter Size Recommended by BeerSmith will not provide you with the number of cells that BeerSmith shows that you need.   
See example attached, where I indicate that I would start with 135 Billion (way more than available in the yeast package), BeerSmith recommends a smaller starter (because I'm starting with more yeast). 
If I change the starter size to match BeerSmith, it Still comes up Short.

I wonder if this is an easy fix...Revision 2.3.6.1 ?

Overall, I like the improvements!  Thanks Brad.
 

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  • More Starting Cells BeerSmith Yeast.JPG
    More Starting Cells BeerSmith Yeast.JPG
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BeerSmith

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I found the bug here and the fix will be in the 2.3.7 update coming shortly.

Brad
 
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