Yeast starter cell count?

[Rubs]

Hello.

I've made a 1L starter from a wlp001 vial, and I stepped it up to a 2L starter, which should provide about 400 billion yeast cells. I cold crashed it, and put it in 4 old vials for storage. But it doesn't really look like it's 100 billion cells in each vial, it looks like there's about half of the original amount of yeast in each vial.

Is this an indication of the actual cell count, or could it be that it's just more concentrated?

 

[flars]

Which of the yeast starter calculators did you use? Would need some more information about your procedure. Time on stir plate and cold crashing time between steps. How many milliliters of yeast are in each vial?

 

[Rubs]

I used the BrewersFriend calc. The starter did it's thing for three days, and I shook it whenever I could. Cold crashed overnight, decanted and pitched into the 2 liter starter the next morning and did it all again. I'll check the millimeters when I get home, but compared to a new vial, it looks about 50%.

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[duboman]

Are you sure all the yeast in each vial has completely flocculated out? You could always count each cell

 

[Rubs]

The vials have been stationary for a couple days now, so I think so. I'm REALLY good at counting though, so I might just do that

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[BBL_Brewer]

I doubt you generated 400 billion cells. According to yeastcalc, you probably have more like 250 billion cells (I don't know how old the vial was). Even using a stir plate and assuming the most optimistic outcome (Zainesheff) you would have only hit ~350 billion cells (assuming the vial was very fresh and viability was high). So I'd say your assumption that you only have about half of a normal vial is correct.

 

[Rubs]

Hmm. That is if I used a 2 liter starter. But I made a 1 liter starter first, and then stepped it up to a 2 liter. According to YeastCalc I should have gotten 364 with intermittent shaking.

Though, I didn't get to shake it as much as I'd like to, and the numbers do look more realistic if I choose "none" aeration.

 

[BBL_Brewer]

Hmm. That is if I used a 2 liter starter. But I made a 1 liter starter first, and then stepped it up to a 2 liter. According to YeastCalc I should have gotten 364 with intermittent shaking.

Though, I didn't get to shake it as much as I'd like to, and the numbers do look more realistic if I choose "none" aeration.

Was your final volume two liters or 3 liters? In other words, did you start with one liter and then add one more liter, or did you start with one liter and then add two more liters? By my calculations, if you started with one liter and added one more liter (final volume of 2 liters) you should have only gotten ~265 billion cells max. If your final volume was 3 liters, then you are correct that it should have been closer to 364 billion.

 

[Rubs]

I made a 1 liter starter, let it finish fermenting, decanted, and pitched the yeast into a 2 liter starter.

 

[BBL_Brewer]

I made a 1 liter starter, let it finish fermenting, decanted, and pitched the yeast into a 2 liter starter.

Gotcha. That's what threw me off. Sorry for the confusion.

 

[Rubs]

No problem!
Well, I guess it's the lack of proper shaking that did it then.

 

[BBL_Brewer]

The good news is, you still have 4 vials now instead of one. You'll just have a to make a bigger starter to use them.

 

[Rubs]

That, my friend, is great news!

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