Stepped Yeast Starter Calculator

[Steve@PMF82]

Done. This was a good suggestion, I think it helps to clarify things a bit. I also changed the "growth rate" label back to "number of doublings". I think these two changes will help prevent confusion. Thanks.

I also bumped the maximum inoculation rate up to 249 million cells/ml, this is literally the highest number the calcs can go to, once the inoculation rate surpasses 249 it actually calculates a negative number of new cells produced.

Once again my thanks goes out to the AussieHombrewers, you guys ROCK! :super:

Very Nice work sulli, you have created a very useful tool for home brewers to make better beer!

 

[mckenry]

This seems pretty good.

I have been playing around with it. Still trying to decide if minimum steps, whilst keeping the innoc rate between 50-100 is the way to go, or evening out step volumes...

One thing though. From the Wyeast webpage, they state 100B cells is enough to innoc 5 gallons. Assuming 100% viability. and OG between 1.034 & 1.060

When I have 100% viability in the calc and 5 gallons at 1.034 - the calc says its underpitching by 21B cells (21%) or at a rate of 1.1mill cells/mL. 21% is enough to think about.

This is without a starter as the wyeast page states its enough to go directly into 5 gallons.

Comments?

 

[Steve@PMF82]

This seems pretty good.

I have been playing around with it. Still trying to decide if minimum steps, whilst keeping the innoc rate between 50-100 is the way to go, or evening out step volumes...

One thing though. From the Wyeast webpage, they state 100B cells is enough to innoc 5 gallons. Assuming 100% viability. and OG between 1.034 & 1.060

When I have 100% viability in the calc and 5 gallons at 1.034 - the calc says its underpitching by 21B cells (21%) or at a rate of 1.1mill cells/mL. 21% is enough to think about.

This is without a starter as the wyeast page states its enough to go directly into 5 gallons.

Comments?

This calculator uses pitching rates same as MR malty calculator / info from Yeast book / Mr white ect.

Wyeast also recommend pitching slightly warmer than your desired ferment temp, which encourages yeast growth and you can subsequently get away with the large SG range they say the packs will inoculate.

For me i certainty would not be treating a 1034 wort the same as 1060.

 

[stux]

End of the day, its in WYeast's best interests to imply you don't need a starter.

Its very hard to get 100% viable Wyeast in australia anyway

 

[mckenry]

Wyeast also recommend pitching slightly warmer than your desired ferment temp, which encourages yeast growth and you can subsequently get away with the large SG range they say the packs will inoculate

For me i certainty would not be treating a 1034 wort the same as 1060.

Oh yeah, for sure. Just wondering why this calc says a new wyeast pouch at 100% viability was a 21% underpitch at OG 1.034
Would only be worse the higher the OG goes.

But as you say, pitching warmer...

I have always just split new packs and built starters anyway, using MrMalty.

Seeing as I can have a pretty good guess at 33.3B cells (1 pack split 3 ways) now I can adjust my steps better.
Question for slurry scavengers. How do you estimate your starting cell count?

 

[dustinsullivan]

Oh yeah, for sure. Just wondering why this calc says a new wyeast pouch at 100% viability was a 21% underpitch at OG 1.034
Would only be worse the higher the OG goes.

But as you say, pitching warmer...

I have always just split new packs and built starters anyway, using MrMalty.

Seeing as I can have a pretty good guess at 33.3B cells (1 pack split 3 ways) now I can adjust my steps better.
Question for slurry scavengers. How do you estimate your starting cell count?

Lot of guys are using mr malty to estimate cell counts from slurry, and then using this number for initial cell count input for yeastcalc

 

[cdbrown]

it would seem that Total Cells at Finish is always green even if the cell count is below the target for the batch. Was working prior to the colour change on the innoculation rate.

 

[dustinsullivan]

it would seem that Total Cells at Finish is always green even if the cell count is below the target for the batch. Was working prior to the colour change on the innoculation rate.

Ugh.

 

[dustinsullivan]

I learned something tonight, logic problems and homebrews do not mix well.
Even so, I think I've got it working properly now. Please let me know if there are any more bugs, I'm going to pour myself another pint :beer:

 

[MaltyHops]

...
Question for slurry scavengers. How do you estimate your starting cell count?

THIS post might apply to your question.

 

[TSMill]

I learned something tonight, logic problems and homebrews do not mix well.
Even so, I think I've got it working properly now. Please let me know if there are any more bugs, I'm going to pour myself another pint :beer:

For 100% viability in the calc I need to obtain yeast 5 days into the future, which in practice I find hard to achieve.

 

[dustinsullivan]

For 100% viability in the calc I need to obtain yeast 5 days into the future, which in practice I find hard to achieve.

I understand. Time travel is not one of my strong suits either. It's on my to do list, though.

 

[dustinsullivan]

For 100% viability in the calc I need to obtain yeast 5 days into the future, which in practice I find hard to achieve.

You no longer need travel into the future, just click the checkbox, and type in your viability.
Been meaning to do this for a long time, thanks for putting a fire under my ass.

 

[ploto]

What would be an estimated cell count to use for the dregs in a bottle? And what sort of viability could you expect to have for something relatively fresh, such as Coopers, or for an imported bottle assumed to be in poor state?

I'm aware of the Wyeast page that MaltyHops linked to above, but I'm not quite sure how to apply it to bottle dregs.

 

[Steve@PMF82]

What would be an estimated cell count to use for the dregs in a bottle? And what sort of viability could you expect to have for something relatively fresh, such as Coopers, or for an imported bottle assumed to be in poor state?

I'm aware of the Wyeast page that MaltyHops linked to above, but I'm not quite sure how to apply it to bottle dregs.

When i culture from a bottle its usually something like 100ml, 400ml, 800ml then into 1.5 to 2L(all just intermittent shaking), let that last step ferment out and clear at ferment temps, then wash the yeast. Using Mr malty slurry calculator get a rough idea about how many yeast cells i may have in measured sample and go from there.

I think trying to guess what live cells remain in bottle dregs would be less accurate.

How i do it is not the most accurate method, buts its repeatable and gives me some idea what im pitching.

EDIT2: I should also add i do use this calculator as well, usually when i have a more "known" sample like from a split smack pack and use the viability based on manufacture date.

 

[Wolfy]

What would be an estimated cell count to use for the dregs in a bottle? And what sort of viability could you expect to have for something relatively fresh, such as Coopers, or for an imported bottle assumed to be in poor state?

I'm aware of the Wyeast page that MaltyHops linked to above, but I'm not quite sure how to apply it to bottle dregs.

You can't apply the Wyeast info, and you can't (really) even have an estimate of the number of cells, because there are too many factors to consider that you do not know the answer to.
It's only after reviving the yeast in a starter that you'll even be sure there is any viable yeast.

 

[ploto]

Thanks for clearing that up. So in other words I should just get the starter up and running first before worrying about cell counts etc.

 

[Wolfy]

Thanks for clearing that up. So in other words I should just get the starter up and running first before worrying about cell counts etc.

Yes, and even then, unless you are using microscope-techniques, any 'cell count' is simply guesswork (semi-educated estimation at best), any figures you 'calculate' will have a huge margin of error.
So, repeatable techniques, ensuring that your yeast is as healthy has possible and eliminating cross-contamination and infection are much more important considerations.

Keeping it simple; a healthy 1 to 2L yeast starter it will be more than adequate (for a standard sized batch of average gravity ale), once you have that mastered, maths and formulas may (or may not) be useful to adjust your procedures.

 

[dustinsullivan]

Yes, and even then, unless you are using microscope-techniques, any 'cell count' is simply guesswork (semi-educated estimation at best), any figures you 'calculate' will have a huge margin of error.
So, repeatable techniques, ensuring that your yeast is as healthy has possible and eliminating cross-contamination and infection are much more important considerations.

Keeping it simple; a healthy 1 to 2L yeast starter it will be more than adequate (for a standard sized batch of average gravity ale), once you have that mastered, maths and formulas may (or may not) be useful to adjust your procedures.

How big a margin of error would you calculate, and what do you base this on?

 

[Wolfy]

How big a margin of error would you calculate, and what do you base this on?

+/- 50% to 100%.
It's based on the assumptions required to estimate a yeast count, compared to actually counting actual yeast cells.
Then you also need to consider that when counting yeast cells the 'established' methods may not be reliable and have a large margin of error (reference 'Yeast' book and methyl-blue staining techniques).
And after that, even the published authors (compare Ray Daniels to John Palmer to Jamil Zainasheff) have vastly different suggestions on the number of cells both required and available in yeast samples - some of these are more than 10x or 100x different to each other.

Look at the MrMalty calculator as one example of the margin of error we are talking about.
For a 1.048 OG 23L brew the amount of yeast-slurry required (working on a fixed 94% viability) varies from 272ml (thin slurry, high non-yeast percentage) to 48ml (thick slurry, low non-yeast percentage) - what huge margin of error is that?
Hence, without actually counting the cells, there is no way to know - without either estimating/guessing (which is what we are talking about here) or counting actual yeast-cells - where within that range any particular yeast-sample lies.

Which is why having repeatable and regular techniques that you follow (and adjust as required) is more important than any mathematical estimate of yeast cells.