Yeast Count: Initial Count and Starter Size

[biertourist]

Does anyone have an updated version of Palmer's "Estimated Final Yeast Cell Count (Billions) Based on Initial Count and Starer Size" chart from HTB (pg 69)?


The chart is great but it only starts with an initial cell count of 35 billion. (A Wyeast propagator smack pack only contains 25 billion cells and if you get an old one you could be dealing with 10 billion cells or less.)

-I've plotted the data points from the chart in Excel and there's definitely nothing linear in there so calculating off of the existing datasheet without a formula is pretty difficult.

The increase in initial population to 1 Liter (or 1 Qt) increases significantly in the initial to final yeast cell count ratio the lower the cell count gets so I think a guestimation of the final population that I'd get pitching 10 billiion cells into a 1 liter starts would be pretty inaccurate.


-The Mr Malty calculator (and every other calculator I can find) excludes an option for using a single yeast pack and building up over multiple starters.

If we had an updated version of the Palmer table that went down to 5 billion cells, it would be easy to calculate the final population of an initial 1 L starter, and then use that new final population as the starting population for a second starter.

Pitching 3.8 packs of old yeast into a starter isn't really feasible; pitching 1 old pack into a small first starter, and then pitching that starter into a second starter is, but I can't find any data on the growth rate for such small initial yeast populations.


Thanks
Adam

[JohnF]

Does anyone have an updated version of Palmer's "Estimated Final Yeast Cell Count (Billions) Based on Initial Count and Starer Size" chart from HTB (pg 69)?


The chart is great but it only starts with an initial cell count of 35 billion. (A Wyeast propagator smack pack only contains 25 billion cells and if you get an old one you could be dealing with 10 billion cells or less.)

-I've plotted the data points from the chart in Excel and there's definitely nothing linear in there so calculating off of the existing datasheet without a formula is pretty difficult.

The increase in initial population to 1 Liter (or 1 Qt) increases significantly in the initial to final yeast cell count ratio the lower the cell count gets so I think a guestimation of the final population that I'd get pitching 10 billiion cells into a 1 liter starts would be pretty inaccurate.


-The Mr Malty calculator (and every other calculator I can find) excludes an option for using a single yeast pack and building up over multiple starters.

If we had an updated version of the Palmer table that went down to 5 billion cells, it would be easy to calculate the final population of an initial 1 L starter, and then use that new final population as the starting population for a second starter.

Pitching 3.8 packs of old yeast into a starter isn't really feasible; pitching 1 old pack into a small first starter, and then pitching that starter into a second starter is, but I can't find any data on the growth rate for such small initial yeast populations.


Thanks
Adam

It's pretty easy to use the Mr. Malty calculator for stepped starters, but the Wyeast calculator lets you do it explicitly.

[thatguy314]

Does anyone have an updated version of Palmer's "Estimated Final Yeast Cell Count (Billions) Based on Initial Count and Starer Size" chart from HTB (pg 69)?


The chart is great but it only starts with an initial cell count of 35 billion. (A Wyeast propagator smack pack only contains 25 billion cells and if you get an old one you could be dealing with 10 billion cells or less.)

-I've plotted the data points from the chart in Excel and there's definitely nothing linear in there so calculating off of the existing datasheet without a formula is pretty difficult.

The increase in initial population to 1 Liter (or 1 Qt) increases significantly in the initial to final yeast cell count ratio the lower the cell count gets so I think a guestimation of the final population that I'd get pitching 10 billiion cells into a 1 liter starts would be pretty inaccurate.


-The Mr Malty calculator (and every other calculator I can find) excludes an option for using a single yeast pack and building up over multiple starters.

If we had an updated version of the Palmer table that went down to 5 billion cells, it would be easy to calculate the final population of an initial 1 L starter, and then use that new final population as the starting population for a second starter.

Pitching 3.8 packs of old yeast into a starter isn't really feasible; pitching 1 old pack into a small first starter, and then pitching that starter into a second starter is, but I can't find any data on the growth rate for such small initial yeast populations.


Thanks
Adam

It's fairly simple to use the mrmalty calculator. I prefer it to wyeast calc because it gives you total numbers of cells, not cells/ml and I'm lazy. Also it can account for viability. You can also use it to account for the situations where you'd crash the yeast / decant the starter wort, where as you can't do that w/Mr. Malty.

Mr malty sets 1 vial to 100 billion cells, so all you have to do is play with the viability. A propigator pack at 100% viability is the same as an activator at 35%.

To use his calc to determine the viability of an activator pack, just set the date like he does. So let's say the viability is 60% by date. To adjust for an activator multiply .6 x .35 = .21 so your viability is 21%

Grow the starter to 1 generation. let's say you get 110 billion cells from the first starter. What you do then, is set the viability to 110% (110/100 = 1.1) and then run another starter from there.

At the end of the day, just remember these are all estimates, as different strains have strikingly different viabilities over time.

[biertourist]

Sorry,

I'm not following you. I don't see how I can get from where I am (knowing the number of viable cells to where I need to be). -How many cells will result from adding my initial cell count to a 1L starter.

I can go to the Mr. Malty calculator and select the "liquid starter" option, then select the date of the yeast (let's say September 2009 because that gives us a very low viability (10%)).

I know that the Wyeast Propagator packs initially have 25 billion cells when fresh, and I know that (from the Mr Malty Calculator) that it's likely that I only have 10% of that 25 billion as viable cells (2.5 billion).

What I need to know is if I pitch this 2.5 billion cells into a 1 L starter how many resulting yeast cells will I have? (Because I will use this as my new starting yeast population for propagation to a 2nd larger starter.)

As far as I can tell the Mr. Malty calculator doesn't help with this at all.

If I select the drop-down option "Continuous Aeration", and drag the slider bar to "use larger starters" it still says that I will need 3 vials or packs and a 3.46 L starter to get to the 177 billion cells that I need for a 1.048 gravity ale in a single step.
-If the slider bar would let me say "single vial" that would be helpful.

The real problem is that I can't find the math behind the calculator anywhere. The Mr. Malty calculator makes the "total yeast cells needed" a constant and the number of packets and the size of the starter as variables; I need the starting yeast population and the yeast starter size as a constant and the final total number of yeast cells as a variable.
-This is effectively what the Palmer chart does but it doesn't go under an initial yeast cell count of 35billion and doesn't get even close to the 2.5 billion cells that someone with a less than 12 month old Wyeast Propagator pack could be dealing with.


Does anyone have a formula or a solution for this scenario?
(Is the math behind the Mr. Malty calculator published anywhere? Or a version of the Palmer chart that goes well below a starting population of 35 billion cells?)

I just found out that Wyeast used to have a "Cell Growth Calculator"; this is pretty much exactly what I'm looking for...
Anyone have a cell growth calculator?
Adam

[thatguy314]

Sorry,

I'm not following you. I don't see how I can get from where I am (knowing the number of viable cells to where I need to be). -How many cells will result from adding my initial cell count to a 1L starter.

I can go to the Mr. Malty calculator and select the "liquid starter" option, then select the date of the yeast (let's say September 2009 because that gives us a very low viability (10%)).

I know that the Wyeast Propagator packs initially have 25 billion cells when fresh, and I know that (from the Mr Malty Calculator) that it's likely that I only have 10% of that 25 billion as viable cells (2.5 billion).

What I need to know is if I pitch this 2.5 billion cells into a 1 L starter how many resulting yeast cells will I have? (Because I will use this as my new starting yeast population for propagation to a 2nd larger starter.)

As far as I can tell the Mr. Malty calculator doesn't help with this at all.

If I select the drop-down option "Continuous Aeration", and drag the slider bar to "use larger starters" it still says that I will need 3 vials or packs and a 3.46 L starter to get to the 177 billion cells that I need for a 1.048 gravity ale in a single step.
-If the slider bar would let me say "single vial" that would be helpful.

The real problem is that I can't find the math behind the calculator anywhere. The Mr. Malty calculator makes the "total yeast cells needed" a constant and the number of packets and the size of the starter as variables; I need the starting yeast population and the yeast starter size as a constant and the final total number of yeast cells as a variable.
-This is effectively what the Palmer chart does but it doesn't go under an initial yeast cell count of 35billion and doesn't get even close to the 2.5 billion cells that someone with a less than 12 month old Wyeast Propagator pack could be dealing with.


Does anyone have a formula or a solution for this scenario?
(Is the math behind the Mr. Malty calculator published anywhere? Or a version of the Palmer chart that goes well below a starting population of 35 billion cells?)

I just found out that Wyeast used to have a "Cell Growth Calculator"; this is pretty much exactly what I'm looking for...
Anyone have a cell growth calculator?
Adam

Go to the calculator and do what I say and get the numbers I'm describing. You'll figure it out. You have to understand 100% is 100 billion cells. You need to set the viability manually to match the numbers you have. 25 billion = 25% of 100billion, so it's the same of as 25% viability.

You use the pogram to tell you that you have 10% viability. However, it's 10% viability on top of the fact that a propigator is 25% of an activator pack. 10% of 25% is .1 x .25 = .025 or 2.5%. So set your starter to a viability of 2.5% and work from there.

You then need to then change the volume of the beer you want to make. what you change it to doesn't matter, but you should do it until the starter recommends 1 pack at 1L (what you wanted to know). for me it was 0.45 gallons of beer. This say it'll give you 15 billion cells. from your 2.5 billion using continuous airation.

Assuming you then chill the beer, decant and repitch, and that 1L is still your limit, you now set viability to 15% (That's the same as 15 billion cells). Again, move the volume of beer you want to ferment up as high as it'll go and still stay at 1L, 1 vial needed. For me that's 2.15 gallons, and it says you'll get 70 billion cells. Again, chill it down, decant and repitch into a starter

Now you have 70 billion cells. That's right 70% viability. Set the calculator to 5.25 gallons, that's 170 billion with continuous aeration, close enough to your 177 needed (only about 5% off)

So that's the process. That said, that's a lot of work. For 3 dollars you could buy a fresh pack of yeast that requires significantly less work to build up. Plus you'll use at least a couple bucks of DME in the process, so really you're not saving anything unless you are using a limited release that's not available. And even then I'd say be sure that you specifically want to use that yeast.

[Nyakavt]

Go to the calculator and do what I say and get the numbers I'm describing. You'll figure it out. You have to understand 100% is 100 billion cells. You need to set the viability manually to match the numbers you have. 25 billion = 25% of 100billion, so it's the same of as 25% viability.

You use the pogram to tell you that you have 10% viability. However, it's 10% viability on top of the fact that a propigator is 25% of an activator pack. 10% of 25% is .1 x .25 = .025 or 2.5%. So set your starter to a viability of 2.5% and work from there.

You then need to then change the volume of the beer you want to make. what you change it to doesn't matter, but you should do it until the starter recommends 1 pack at 1L (what you wanted to know). for me it was 0.45 gallons of beer. This say it'll give you 15 billion cells. from your 2.5 billion using continuous airation.

Assuming you then chill the beer, decant and repitch, and that 1L is still your limit, you now set viability to 15% (That's the same as 15 billion cells). Again, move the volume of beer you want to ferment up as high as it'll go and still stay at 1L, 1 vial needed. For me that's 2.15 gallons, and it says you'll get 70 billion cells. Again, chill it down, decant and repitch into a starter

Now you have 70 billion cells. That's right 70% viability. Set the calculator to 5.25 gallons, that's 170 billion with continuous aeration, close enough to your 177 needed (only about 5% off)

So that's the process. That said, that's a lot of work. For 3 dollars you could buy a fresh pack of yeast that requires significantly less work to build up. Plus you'll use at least a couple bucks of DME in the process, so really you're not saving anything unless you are using a limited release that's not available. And even then I'd say be sure that you specifically want to use that yeast.

Good summary.

The mr. malty calc has a couple of built in limitations. First is that it will not recommend more than 6 'yeast packages' worth of growth. The reason for this is that you want to ensure that the starter finishes quickly so that you don't end up growing other bugs or yeast instead of the yeast you are trying to grow.

The second limitation is that it will only recommend a minimum of a 1L starter. This is problematic especially for smaller starting cell counts, as 1L really is not ideal for a starting count of this size. You can get around this by scaling down the starter size and calculating the new growth per liter of starter wort. For example, another way of saying that a 2L simple starter grows 100 billion new cells is 'pitching 50 billion cells/L grows 50 billion new cells/L'. Then you can scale down, so if you start with 2.5 billion cells and pitch into 50 mL of wort, you will grow 50 billion new cells/L, or 50*.05=2.5 billion new cells, for a total of 5 billion after step 1. You can plot the mr. malty output and create a calculator to do this in excel or whatever with a simple curve fit, for example the figure below for a stir plate. The x-axis is the starter pitching rate (billion cells/L) and the y-axis is the *new* cell growth, don't forget to add the starting cell growth to the new growth to get your total count after a step.



The final concern of using the mr. malty or the wyeast calc for multiple steps is that they have no limitation for the minimum second step size. The generally accepted minimum is 1L per 100 billion cells, so if your viability is 200% after step 1, you should not make a starter smaller than 2L. The trick is sizing your first steps so that you do not need to split off the yeast to avoid violating the minimum starter size.

[thatguy314]

Another consideration to remember, is that even if you can make your starter really big, you never want the cell count to grow beyond 10x its current size.

[biertourist]

EXACTLY what I was looking for; thanks a million, guys!

(The Wyeast site has beaten into me not to increase the yeast pop more than 10x, for sure.)



Adam