Stepped Yeast Starter Calculator

[haysie]

When you pitch increasingly larger quantities of yeast into small volume starters, they consume all the nutrients very quickly and do not grow at all (reference table on page 140 "Yeast" book)
In addition if you listen to the BN podcasts featuring Chris White, he says quite clearly that pitching 1 new pack of yeast into small starter (500ml in your case) will result in little to no growth, so (from what I have read, listened to and understood) there appears to be little basis for any of the growth factors or assumptions that you have made above.

I`ve always been a tad unconvinced re. the 6x and 10x that seems to be talked about a lot, i.e 1 pack of yeast x 6 = 600 ml starter.
Today I split a fresh pack of Wyeast1056 at approx 1pm, I didnt split the nutrient pack so the volume is about 90ml of yeast liquid. I took 4 x 15ml vials from the pack and added the remaining 30 ml to a fresh 1ltr starter (so thats about 35x). Just got in the door and the starter having been spinning the last 3 hrs is going off, huge krausen.

 

[BjornJ]

Hi guys,
I hope this is not too off-topic as it leads towards the same goal : pitching enough yeast.

Rather than doing massive starters for lagers, would "douple dropping" do a similar kind of thing?

Thinking something along the lines of:
Stir plate starter of say 2 litres from Whitelabs vial.
Pitch entire 2L starter into 23 litres of wort at 15 degrees.
Next morning (say 10-15 hours later), splash wort from tap into another fermenter to add more oxygen.
Set temp to 11 degrees and leave to ferment.

Would the "double dropping" of aerating the wort by transferring it to another fermenter help to ensure enough yeast?

(and hopefully not create diacetyl)


After making several lagers and stir plate starters I don't think I am pitching enough yeast.
Thinking of if trying again maybe the double drop technique would help the yeast grow bigger.



thanks
Bjorn

 

[Wolfy]

I`ve always been a tad unconvinced re. the 6x and 10x that seems to be talked about a lot, i.e 1 pack of yeast x 6 = 600 ml starter.
Today I split a fresh pack of Wyeast1056 at approx 1pm, I didnt split the nutrient pack so the volume is about 90ml of yeast liquid. I took 4 x 15ml vials from the pack and added the remaining 30 ml to a fresh 1ltr starter (so thats about 35x). Just got in the door and the starter having been spinning the last 3 hrs is going off, huge krausen.

That's because you are right ... but you're just looking at it the wrong way.

The "100million cells per ml" that TB is talking about on the previous page is the estimate for the density of yeast in a normal concentration of starter.
A Wyeast pack is super-concentrated highly viable yeast, 30ml of concentrated-yeast from that pack should have about 30billion cells, which is the equivalent of a 300ml starter.
Hence, by pitching 30ml of a Wyeast pack into 1L starter the step-up ratio is about 4x not 35x.
If you were to pitch 20ml of fresh-pack yeast into a 1L starter, you'd be stepping up about 5x (to 10x depending on age of the pack) which is close to the ideal step size.

Rather than doing massive starters for lagers, would "douple dropping" do a similar kind of thing?

Yes ... there is some historical information that German brewers used to do something very similar, although they had a different name for it, I think there is a link from BribieG's thread, either here or on JBK.

 

[Thirsty Boy]

I think that what you arethinking of is Drauflassen. Or double batching. Not the same thing as double dropping from teh English brewing tradition.

Its about pitching your yeast to a portion of your wort, then later adding some more wort in one or more steps just before the yeast gets to fully active fermentation.

Something thats really very easy for a no-chill brewer to do, one cube - pitch - wait 12 hrs or so - pitch next cube. Similar effect in alot of ways to double dropping in that it adds oxygen, but its also kind of like a supersized starter and keeps the yeast in lag phase for longer because it kind of "tricks" them into thinking they are in a differeent environment to the one they are really in.

But don't be tricked into thinking that you now get to pitch just a single pack into your double batch of bock. It still works out that you really want to add 2/3rds of the proper amount of yeast for the whole wort amount (OK, maybe you will get away with half) so it can be handy if your calculations tell you that you need 7L of starter and you only have a 5L flask.... But it isn't knocking something like a 7L starter down to being able to do it in a 2L flask or anything quite qs dramatic as that.

I'm afraid that if you want to make lagers, and you want to pitch at the recommended rates, you just have to pony up for a big arsed vessel to do it in, or re-pitch yeast from a previous batch.

Braukaiser has a nice article on it ( http://www.braukaiser.com/wiki/index.php?title=Drauflassen ) although when he is trying to give you a way to manage the process at a HB level he has it harder than we enlightened folks, because he cant use No-Chill to help him make it easy.

 

[felten]

Pick a bunch of styles that fit the yeast you want to use, and brew them in a progression with re-pitched yeast like TB said.

I'm stuck with a 2L flask as well, and that's the way I would go about it. Even then it's still a PITA because a small starting lager will still require a large (~3L) starter.

 

[BjornJ]

thanks, read the Drauflassen article now.
Maybe that's what I can try next.

thanks
Bjorn

 

[stux]

Based on what TB said about yeast growth, I've whipped up this simple spreadsheet.

View attachment Yeast_Stepping_Calculator.xlsx


The idea is that yeast in a starter will only grow to a certain density.

For example, 100Mcells/mL if you only allow 12-18 hrs of growth, but if you were to allow the yeast to fully ferment then you might expect 150Mcells/mL

This spreadsheet assumes a fixed maximum growth density (which can be changed) and then iterates step sizes assuming a certain growth factor.

I split my WYeast activator packs 4 ways to end up with 30mL vials with the same cell density as the original package.

So for example,

to obtain circa 525 Billion yeast cells (to pitch 55L of 1.052 Ale) you might start with 30mL of 56% viable WYeast, and then apply a growth factor of 6.25x

which at 100Mcells/mL starter density limit would mean I should pitch my 30mL vial into 840mL of wort, that'd then grow to 100Mcells/mL which is also a 6.25x growth factor, which I would then pitch into 5,250mL for a total of 525 Billion cells after 2 steps.

That's assuming 100Mcells/mL

If I were to assume 150 then the steps would be 560 and 3,500mL, respectively.

Of course, since we're assuming a fixed density the interim steps don't really matter that much, and in fact I could use 500 and then 3500, or whatever.

The other interesting thing is, once you have worked out your growth factor to use to get your final yeast count, then the maximum growth density just reduces the amount of wort required in your starters...

Now, the problems?

I'm assuming a certain maximum density. This does not correlate well with Mr Malty, but if you use 78 for the Growth Max Density, then it does correlate with a stirred starter from a single vial.

Also, I'm not calculating the differential step size, only the pure final volume, assuming 1.040.

Thoughts?

 

[matho]

Have you also tried playing around with This

Cheers matho

 

[Wolfy]

Thoughts?

Firstly, I can't actually look at the spreadsheet since it seems I use an antiquated version of Office, so my comments are based only on what you said above.

When using stepped-yeast-starters, the MrMalty calculator becomes less and less useful, since the calculator is designed ONLY to work when inoculating a single step-starter with a pack of liquid yeast, and since that nearly always means you are pitching at a very high inoculation rate, the results are not always applicable to stepped starters.
The Wyeast calculator does allow for fractions of packets to be used, so you might find that more useful, if it correctly adjusts for the 1/4 pack that you use for your initial pitch, so its worth testing your numbers against that.

However, from memory it is usual to expect yeast cells to spit maybe 2 or 3 times, this is usually called the 'growth factor' and if you are using more than 6x for the same thing it may be a little unrealistic.

While I'd suggest that the previously mentioned '100million per ml' is a good maximum cell density to base calculations on, it also makes it so simple to work out the required starter size, that one could not possibly need a spread sheet for it. 525 billion cells = 5.25L it's a no-brainier, so your spreadsheet must do more than that.

It also seems that you have not taken into account the Inoculation Rate, but even then based on info on page 140 of the 'Yeast' book, when using an inoculation rate of anywhere between 25 and 125 million cells/ml you'll get much the same Yield factor (growth rate). However since there is a huge spread between those numbers, it mostly indicates that pretty-much-anything will work, especially keeping in mind that the 'industry standard' step size is 10x the previous volume.

Having said all that, you know the number of cells in your split-pack (adjust the usual 100billion total number of cells in the pack against manufacture date as per the MrMalty calculations) and you know the final volume (based on the maximum cell density of 100million per ml), so then all you need to do is apply an inoculation rate of anywhere between 25 and 125 million cells/ml. Interestingly, I'd guess that those numbers work out that mostly any resonable starter/step size will work, and only 1 step is required between the 1/4 of a pack and the total volume required.

 

[stux]

Firstly, I can't actually look at the spreadsheet since it seems I use an antiquated version of Office, so my comments are based only on what you said above.

Excel 2004 Version

View attachment Yeast_Stepping_Calculator.xls

When using stepped-yeast-starters, the MrMalty calculator becomes less and less useful, since the calculator is designed ONLY to work when inoculating a single step-starter with a pack of liquid yeast, and since that nearly always means you are pitching at a very high inoculation rate, the results are not always applicable to stepped starters.
The Wyeast calculator does allow for fractions of packets to be used, so you might find that more useful, if it correctly adjusts for the 1/4 pack that you use for your initial pitch, so its worth testing your numbers against that.

However, from memory it is usual to expect yeast cells to spit maybe 2 or 3 times, this is usually called the 'growth factor' and if you are using more than 6x for the same thing it may be a little unrealistic.

I think the issue is what I have called "Growth Factor" is actually step size

If you're doing step sizes of 10 fold, and you're always ending up with 100million/mL, then you have total growthof 9 fold, which I guess means the yeast split 2 and bit times? And that "2 and a bit" is that the true growth factor?

While I'd suggest that the previously mentioned '100million per ml' is a good maximum cell density to base calculations on, it also makes it so simple to work out the required starter size, that one could not possibly need a spread sheet for it. 525 billion cells = 5.25L it's a no-brainier, so your spreadsheet must do more than that.

Yes, it splits the steps based on a maximum step size

It also seems that you have not taken into account the Inoculation Rate, but even then based on info on page 140 of the 'Yeast' book, when using an inoculation rate of anywhere between 25 and 125 million cells/ml you'll get much the same Yield factor (growth rate). However since there is a huge spread between those numbers, it mostly indicates that pretty-much-anything will work, especially keeping in mind that the 'industry standard' step size is 10x the previous volume.

Exactly, assuming we reach maximum cell density, then the innoculation rate doesn't matter so much, what I'm trying to do is have the innoculation rate be the same for each step to minimize cell growth required at each step, before fresh wort is added

Having said all that, you know the number of cells in your split-pack (adjust the usual 100billion total number of cells in the pack against manufacture date as per the MrMalty calculations) and you know the final volume (based on the maximum cell density of 100million per ml), so then all you need to do is apply an inoculation rate of anywhere between 25 and 125 million cells/ml. Interestingly, I'd guess that those numbers work out that mostly any resonable starter/step size will work, and only 1 step is required between the 1/4 of a pack and the total volume required.

Exactly

It is interesting to play with the step size and maximum cell density, the step size basically gets you to a certain number of cells after a certain number of steps, and the max density changes the amount of starter you need for those cells...

 

[matho]

Hey wolfy the wyeast calculator does let you use fractions of the pack just put 0.25 in the no. of packets box

Cheers

 

[stux]

Hey wolfy the wyeast calculator does let you use fractions of the pack just put 0.25 in the no. of packets box

Cheers

I actually tried using "Propogator" which is a 30 ml packet and then "0.56" for the quantity which then becomes the viability

 

[matho]

Don't worry about me I'm not reading very well tonight wolfy said does and I read doesn't

 

[matho]

i actually plotted some numbers off the wyeast calculator onto a spreadsheet

View attachment yeast.xls

this was done on open office and save as an xls if the graphs dont come up here is what they look like



as you can see the growth rate varies a bit in the calculator

cheers

 

[Wolfy]

Hey wolfy the wyeast calculator does let you use fractions of the pack just put 0.25 in the no. of packets box

Yeah the calculator lets you put numbers in, I was more questioning its accuracy, especially at lower pitching rates, since I presume it was designed to be accurate for full or even multiple packs and higher pitching rates.

 

[Wolfy]

I know this is an old thread, but a post I just made on the UK JBK forums made me realize how easy it is to work out.

Based on the assumptions mentioned by TB on the previous page - it should all come down to a few easy steps:

• Work out how much yeast you need to pitch (1 million cells of viable yeast, for every milliliter of wort, for every degree plato, adjusted for the type of beer you are brewing (or just use MrMalty it does this for you))
• Assume a maximum cell density to determine the required starter volume size (100million cells per ml, 100billion per L as per TB's info on previous page).
• Determine your starter pitching rate (10milion cells per ml pitching rate, as per TB's info on previous page)
• Step that starter size 'down' by a factor of between 5 and 10, progressively until you get to the number of yeast cells you assume you are starting with
• Adjust the step sizes and starter volumes to make them more even/logical

Example: Brewing 40L of Ale at 1.045, starting from 1billion cells (an older split yeast pack or a 10ml starter from a slant).

• We need 336 billion yeast cells (apply calculation or use MrMalty)
• That equates to 3.4L starter
• Step that starter down by 10x is a 340ml starter (into which we need to pitch 3.4billion cells, our 1billion is not yet enough so step again)
• Step that down by 10x to 34ml (we need to pitch 0.34billion cells so we are at/below our starting target of 1billion cells)

Now to even the step sizes and make the starter volumes more sensible:

• Start with 1billion cells from 10ml slant-starter or old split yeast pack
• Step up by 7x into 70ml starter (~7billion cells)
• Step up by 7x into 500ml starter (~50billion cells)
• Step up by 7x into 3.4L starter (= our required 340billion cells)

The process is quick and easy, however I have no idea how to put that kind of logic into a spreadsheet, especially when step sizes anywhere between 4x and 10x are equally valid and one step might be 5x and the next could be 10x and it would still work fine.

 

[stux]

This is how my spreadsheet works

Except it doesn't iterate. But you enter 7x, you get your 7 fold result

 

[Wolfy]

This is how my spreadsheet works

Except it doesn't iterate. But you enter 7x, you get your 7 fold result

Yeah, I used a table to show the various step multipliers that I can then manually lookup to find the result, works for me, but it needs to be automated before it is user-friendly.

 

[dustinsullivan]

A very good idea. Here is my take on the whole thing YeastCalc

 

[stux]

A very good idea. Here is my take on the whole thing YeastCalc

Neat

Can you add an option to use L for batch size?