How much of my oversized starter to use?

Hello,
To save a little cash, I made a 1.6L starter (stir plate) last weekend and only pitched 1L into my dry stout. I used the rest to make a 1.5L starter for my next batch, which according to Mr.Malty, requires 148 billion cells or a 1L starter (it's a 1.040 bitter), allowing me to save .5L.

The yeast is WLP007, has really flocculated, and is really clumpy in the starter, so it's not really a homogeneous solution that I can just split up easily.

If I cold crash to get the yeast out of suspension, can someone help me figure out how much of this (in mL) I need to pitch and how much I can save for the next time? I'm not sure how to use Mr.Malty to figure this out.

Thanks for all your help,
John

Estimate 1 billion cells per milliliter since the yeast is clumpy. There could be up to 2 billion per ml, but over pitching has far less serious consequences than under pitching.
This yeast calculator will help you out with how many yeast cells you need for the OG of your beer.
Definitions used for selecting the pitch rate is below the calculator. I use 0.75 Pro Brewer for all my average gravity ales.

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

148 billion cells at 1 billion/mL is 148mL. Seems reasonable, and it looks like I have more than enough in my starter to cover that.

Thanks!
John

I would cold crash it. Then measure either volume or weight to achieve two thirds. If you're making more of a starter than is needed it is helpful to have an accurate scale and check your vessels' dry weight ahead of time. I find slurries to be more of a guess than "known"starter numbers. The thickness of the slurry can have a large impact on pitch numbers. But whatever your comfortable with, and is going to ensure reduced contamination, is the way to go.

Lesson here; figure out your game plan ahead of time. Good luck! I'm sure the beer will be good!

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You can't shake it up enough to be homogenous? Do that then measure it out. Chuck the leftovers in your boil, no point wasting it.



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