Starter Size and cell count

[farmskis]

Just a question I have….

Starter 1) 1.040 1 L add in 100 billion cells

Starter 2) 1.040 1L add in 50 billion cells.

Will the end cell count between the two starters be roughly the same, given enough time for the yeast to reproduce?

Basically curious if the beginning yeast will just reproduce until a certain saturation point.

 

[day_trippr]

This calculator when forced to consider 1 liter of 1.040 wort in a 2 liter flask with 100% of the pitched cells being viable shows 50B cells producing 203B cells total vs 100B cells producing 253B cells total.

https://www.brewunited.com/yeast_calculator.php

Cheers!

 

[farmskis]

This calculator when forced to consider 1 liter of 1.040 wort in a 2 liter flask with 100% of the pitched cells being viable shows 50B cells producing 203B cells total vs 100B cells producing 253B cells total.

https://www.brewunited.com/yeast_calculator.php

Cheers!

A little off of topic but maybe you can help.
If I create a starter and it is supposed to end with 300 billion cells but I want to save 150 billion for another brew… is it good practice to cold crash, decant and then divide the slurry equally to get roughly the 150 billion cells? Or would you stir up the starter real well and divide it, then cold crash both and they both have roughly 150?

 

[mashdar]

Most calculators I'm familiar with (including the link above and brewersfriend) use Braikaiser's results. If you want some good reading re yeast counts, check out his blog. (It's from ~2013)

Based Kai's results, there IS a point at which yeast seem to max out on cell density, and some diminishing returns approaching it. But for most normal starters, it's not a huge deal.

edit: so generally cell count increase is a function of available food and O2

edit: here's the last technical post
https://braukaiser.com/blog/blog/2013/07/07/yeast-growth-on-malt-and-sugar/
I sometimes just flip through his posts (there's a next/prev button). I still find interesting nuggets.

edit: one more, lol
https://braukaiser.com/documents/Troester_NHC_2013_Step_Up_Your_Starter.pdf
Here's his 2013 NHC slideshow. Very dense with findings.

 

[day_trippr]

[...]
If I create a starter and it is supposed to end with 300 billion cells but I want to save 150 billion for another brew… is it good practice to cold crash, decant and then divide the slurry equally to get roughly the 150 billion cells? Or would you stir up the starter real well and divide it, then cold crash both and they both have roughly 150?

I always over-build so I can set aside enough to do a single 5 liter spin for the next over-build while producing enough yeast to pitch 11 gallons of say 1.075 wort using the "hybrid" pitch rate of 1M cells/ml/°P. That requires 700B cells to pitch and 350B to stash. When that spin is done I hard-crash over two days to try to avoid selecting just the easy-to-crash cells. Then I split it into three mason jars, two to use and one to stash...

Cheers!

 

[bestcoast]

I do the same overbuild method as day_trippr, though with smaller volumes because I brew 2.5 gallon batches. I've always cold crashed for a day or two, poured off most of the wort, swirled up the remainder, and then divided that between two 8 oz jars. One goes in my brew and one goes in the fridge for next time I make a starter.

I haven't tried splitting the starter and then cold crashing separately. Seems like a hassle for little benefit, but would be interested if anyone has a reason why that would be better.

 

[marc1]

I do the same overbuild method as day_trippr, though with smaller volumes because I brew 2.5 gallon batches. I've always cold crashed for a day or two, poured off most of the wort, swirled up the remainder, and then divided that between two 8 oz jars. One goes in my brew and one goes in the fridge for next time I make a starter.

I haven't tried splitting the starter and then cold crashing separately. Seems like a hassle for little benefit, but would be interested if anyone has a reason why that would be better.

I find splitting and cold crashing separately easier. I pour off from my large culture on the stir plate into a small jar for storage and larger jars for current use. After cold crashing, the small jar stays in the fridge. The large jars get decanted just before pitching.