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-   -   How to know how many yeasies I have (http://www.homebrewtalk.com/f163/how-know-how-many-yeasies-i-have-370566/)

panfishrfun 11-28-2012 03:57 AM

How to know how many yeasies I have
I have been washing my yeast from my batches of beer, and have quite the collection going. I have made a starter for previous batches (5 gallon), and have got to an expected final gravity. However, I am going to make a big beer, and I am worried there is not enough yeast. I was using Mrmalty.com calculator, and it says I need 339 billion cells for the 1.091OG...how do I know how many cells I have when I collect yeast from previous batches?? Would I be fine if I just stepped this up once, or do I need to at all? It is just a 5 gallon batch.

BBL_Brewer 11-28-2012 04:09 AM

After you make a starter, you can estimate your cell counts by volume. Wyeast has a volume guide in their Pitching Rate Section. Follow the link and scroll down to the bottom. Puts you in the ball park.

panfishrfun 11-28-2012 04:53 AM

So do I just compare my total starter volume to those vial pictures. Or do I need to suspend my yeast and pull out a 1 ml sample and compare that

diS 11-28-2012 08:07 AM

It is better to pour some starter (after mixing it well) in test vial, cold crash it and then estimate density by link BBL Brewer posted.
I am using 10 ml graduated cylinder and I estimate before making starter, after yeast settles I count percent of solids in 10ml and then calculate density for starter volume.
After that you can use some of calculators to see how big starter you need.

WoodlandBrew 11-28-2012 12:29 PM

Short of using a microscope that's probably the best way to do it. Keep in mind it's an estimate, and if you want a clean beer it's probably better to estimate high, and if you want some fruitiness you may consider estimating low. From the cell counts I have done even the cell density of the "yeast solids" can easily vary by a factor of 4. If you use a starter then you eliminate the variability of the "non-yeast" component, and you can fairly safely assume a viability of 95% or higher.

Just to put some numbers on it my WLP004 is about 250 billion cells per liter and my WLP566 packs to a dense 1,750 billion per liter.

panfishrfun 11-28-2012 03:04 PM

Thanks a lot for the responses fellas, this brought up another question though. Say I don't have enough cells, and I need to make another, larger starter, how do I calculate how much DME and water to use for the step up?

WoodlandBrew 11-28-2012 03:20 PM

I would think yeast calc will get you pretty close. Just turn off the "viability by date" option and enter the number of cells you think you have for the "initial cell count" The experiments used to produce the growth curves were with a 1.036 wort so I would use that.

HBngNOK 11-28-2012 03:24 PM


Originally Posted by panfishrfun (Post 4629019)
Thanks a lot for the responses fellas, this brought up another question though. Say I don't have enough cells, and I need to make another, larger starter, how do I calculate how much DME and water to use for the step up?

That's where this guy comes in handy.

never mind, I didn't read the previous post well enough.... :o

panfishrfun 11-29-2012 05:56 AM

2 Attachment(s)
Sorry, I don't know if I really get this...you're supposed to take the washed yeast, and figure out how much yeast you have before you make the starter, then use the yeast calculator to determine the starter size and number of steps used to achieve determined number of cells??

If so, here's a picture of the original washed yeast in a 16 oz mason jar...is there any way from this container to determine how many yeast cells are present?

If i guesstimate there are 100 billion cells (standard setting on yeastcalc) with my original 0.8L starter @ 1.040OG, then, according to the calculator, I need to make another starter @ 1.75L to achieve my 323 billion cells??

325 billion determined from

(0.75 million) X (milliliters of wort) X (degrees Plato of the wort)

750000 X 20,820 X 20.7 = 323 billion

and does the difference in yeast count matter between this equation and yeastcalc suggestion (340 billion)...I imagine it's negligible at this level

Also, just to make sure, the starter volume is post boil correct?

diS 11-29-2012 07:57 AM

Thick slurry usually have between 2-2.5 billions/ml. You can get a test tube and estimate per wyeast instructions.
Or take same jar and fill it with water to get same level as it is in 1st jar, after that measure volume of water.

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