I washed some yeast ( US 05 ) from my last brew; and I now have 3 jars of yeast which separated out nicely overnight. They're around 2/3 yeast, 1/3 liquid at the moment, with no trub as far as I can see.

I want to use one of these next week and I'd like to know how much to use, so I went on to Mr Malty's calculator ( re-pitching from slurry tab ). There's a slider for "yeast concentration" which alters the result considerably. I know that within a week I definitely wont have a "Thin Slurry" at the lower end of the scale but how close to the upper end of the scale ( "Thick Yeast" ) would I likely be considering it will be a week settling in the fridge - or how would I go about estimating this.

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1 Answer 1


Without doing a cell count using dye, microscope and hemocytometer. You really won't know the viable cell count. Otherwise it's all just guessing based on apperances and volumes.

I would just pitch a single jar in 5gal and get on with life.

  • Well I see what you're saying and it makes 100% sense to me but at the same time I looked again at the jars and they all have very different amounts of actual yeast in them - and one has double what another is for instance, and I'm new at all this too. Since there's a calculator there I might as well make use of it - based on your philosophy I think I might just take my own guess at the yeast concentration and err on the over-pitching side. Commented Nov 10, 2016 at 19:22
  • @byronyasgur typically a slurry will settle into a couple layers bottom dark, middle cream, top liquid. This cream layer is your most viable yeast, you can use that visual for your % of yeast. To error on the side of over pitch is good. The majority of styles welcome an over pitch of yeast. Commented Nov 11, 2016 at 0:38
  • @byronyasgur also I would just assume 1bil cells per ml of healthy yeast. For example a can of imperial fresh liquid yeast only has 1.33b cells per ml Commented Nov 11, 2016 at 0:42

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