Calculating yeast starter viability.

[beervoid]

Hi everyone.

I'm overbuilding my starters in order to keep some for a next brew.
Now I could find multiple calculators online to calculate the viability of dated commercial packaged yeasts but none that give you the viability of a starter.

I usually use my starter within a few days but what if you cant brew for lets say a month.
I can imagine viability of a starter dropping faster then a new package.
Is there any rule of thumb or way to calculate viability?

Cheers!

 

[Rob2010SS]

Hi everyone.

I'm overbuilding my starters in order to keep some for a next brew.
Now I could find multiple calculators online to calculate the viability of dated commercial packaged yeasts but none that give you the viability of a starter.

I usually use my starter within a few days but what if you cant brew for lets say a month.
I can imagine viability of a starter dropping faster then a new package.
Is there any rule of thumb or way to calculate viability?

Cheers!

When you make a starter, you're essentially creating new yeast cells right? So essentially you're yeast has a manufactured date of approx 24 hours after you pitch your yeast into your starter. If you plug this date in as your package date or manufactured date, this would tell you your viability. I think...

 

[day_trippr]

^That^ better work because I've been doing it that way for years

I farm almost a dozen strains by doing over-builds, keeping at least 100ml of thick slurry per strain.
I've resurrected yeast up to 11 months in the jar with no real issues, just needed an extra step or sometimes two (pitching 11 gallon batches)...

Cheers!

 

[beervoid]

When you make a starter, you're essentially creating new yeast cells right? So essentially you're yeast has a manufactured date of approx 24 hours after you pitch your yeast into your starter. If you plug this date in as your package date or manufactured date, this would tell you your viability. I think...

Well I would think that.

1. Every time you overbuild and harvest you also harvest some old yeast.
2. I assume a new package from a yeast producer is made under sterile conditions unlike most homebrew setups.

 

[beervoid]

^That^ better work because I've been doing it that way for years

I farm almost a dozen strains by doing over-builds, keeping at least 100ml of thick slurry per strain.
I've resurrected yeast up to 11 months in the jar with no real issues, just needed an extra step or sometimes two (pitching 11 gallon batches)...

Cheers!

That's comforting to read. I've been using the production date calculation method for now but as I am a control freak I would love to be able calculate this better.
Cheers for sharing.

 

[RM-MN]

How about this research on viability?

http://www.woodlandbrew.com/2012/12/refrigeration-effects-on-yeast-viability.html