Author Topic: yeast starter for beersmith if you want to use slurry  (Read 4484 times)

Offline Watto

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yeast starter for beersmith if you want to use slurry
« on: November 11, 2016, 01:45:43 AM »
Hi All

This topic would have been posted a few times for sure but I can't find the answer I want about adding yeast slurry in on the beer smith software. The numbers don't add up. In the recipe building part on the starter tab how do you enter a surry in. Is there a video  or can someone explain what to do thanks. 


Offline Oginme

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Re: yeast starter for beersmith if you want to use slurry
« Reply #1 on: November 11, 2016, 05:38:08 AM »
First, I am not sure if you are referring to a repitch slurry or a starter so I will address both.

For a yeast starter, I have attached a screen grab of the starter tab for a recipe.  Make sure that date for the yeast in BeerSmith is updated to match the packaging date on the yeast package.  Now, in the section circled in red, you can enter the actual size of the starter and the gravity reading of the starter into BeerSmith.  Note that you can opt to add this starter volume to the fermentor and count it in your bottling volume (blue arrow), or as I usually do, cold crash it and decant the wort from the starter.

If you are repitching a yeast starter, it becomes a little more tricky.  If I have done a yeast count on the recovered slurry, I create a copy of the yeast in the ingredient file and relabel it as a *(repitch).  Then I define a unit as 1 ml and enter my viable yeast count per ml as the 'cells per pack' for that yeast.  I can then enter the ml of yeast slurry I intend to pitch and compare that to how many cells the program recommends I pitch.

Most of the time, I don't have the time/energy to do a cell count so I estimate the number of cells per ml of yeast slurry.  I decant excess wort from the harvested slurry and examine the yeast concentration for how much yeast vs how much trub was collected.  Generally, I have about 20% to 30% trub in the yeast collected.  A thick yeast cake will have approximately 4 to 5 billion cells per ml when 100% yeast.  I proportion this by the amount of trub that I think I have in the captured slurry so that if I guesstimate 30% trub, I use a cell count of 70% x 4 billion cells or 2.8 billion cells per ml of slurry.  I can then enter this as above as the 'cells per pack', defining a pack as 1 ml of yeast slurry.

If the yeast cake is somewhat diluted, I will account for that as well by estimating the extra amount of water/wort in with the yeast and discounting the cell concentration by that amount.

I usually try to stay pretty conservative with my yeast estimations, erring high on trub concentration, low on the cell count.

Hope this helps.
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Offline Watto

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Re: yeast starter for beersmith if you want to use slurry
« Reply #2 on: November 12, 2016, 12:57:16 AM »
Hi Thanks for the reply that answers all my questions. Sorry if the question was a bit light on. I do have one more thing I cant get my head around and it might be an easy one for some but I'm new to this. What does the volume of slurry needed at the bottom of the yeast starter tab mean. Its seems like a lot. How do you apply it.  I have attached a photo

Thanks for the help.

Offline Oginme

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Re: yeast starter for beersmith if you want to use slurry
« Reply #3 on: November 12, 2016, 05:15:54 AM »
The volume of yeast slurry refers to a repitch of yeast from a previous fermentation, covered under the second and third scenarios I outlined.  Honestly, I have not paid much attention to its accuracy as I don't see where it takes into account the yeast concentration and thickness of the slurry.
Recycle your grains, feed them to a goat!

Offline Watto

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Re: yeast starter for beersmith if you want to use slurry
« Reply #4 on: November 12, 2016, 02:29:48 PM »
Thanks for that i don't think I will take to much notice of that information. I will just work it out from the information from your first reply. Thanks for the help have good one. 

 

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