Stepping up yeast starters. What am I missing here?

[rtt121]

Good morning ladies and gents,

I have a question hopefully someone can help me with. I have used BillyB's article regarding stepping up a yeast starter with great success. (Article)

I am going to use an example to make explaining my question easier. I would like to brew 11 gallons of a 1.058 lager. Mr Malty shows that I need 888 billion cells. Using the chart from YEAST posted by BillyB shows that I can get these 888 billion cells by:


A: Adding 200b (2 smack packs) to 2l of wort: 300b
B: Adding 300b to 4l of wort: 500b
C: Adding 500b to 6l of wort: 800b (let's call that close enough)

The problem comes about when I factor in that he says "Please note that this study was done with no added oxygen. Adding oxygen with a stir plate or by shaking will roughly double the amount of growth you get". Well I would rather not make 4 different step ups if I can avoid it.. plus I have a a stir plate. So what I have done is recreated the chart doubling all of the yeast cell counts in the x axis. My recreated chart with doubled yeast is attached.

This shows me that adding 200b cells (two smack packs)to 4l will yield the 800b cells in one step. Great right?!

BUT when I go back to Mr. Malty and use 1.058, Lager, 11 Gallons, Fewest Smack Packs, and Stirplate Starter the result is that I need 2 Smackpacks and 12.46 liters of starter.

So what am I missing here? My guess is that it isn't as easy as simply doubling the x axis but the information provided comes from the book "Yeast" (or so BillyB says. I do not own the book) which is written by Jamil Z who also authored Mr.Malty Pitching Rate Calc.

Any help would be greatly appreciated!

 

[flars]

See if this pitch rate/starter calculator answers some of your questions. It is easy use and presents the numbers in a clear format.
http://www.brewunited.com/yeast_calculator.php
The calculator also has an overbuild option for harvesting yeast from your starter for the next brew session if you don't harvest from the fermentor.

 

[rtt121]

See if this pitch rate/starter calculator answers some of your questions. It is easy use and presents the numbers in a clear format.
http://www.brewunited.com/yeast_calculator.php
The calculator also has an overbuild option for harvesting yeast from your starter for the next brew session if you don't harvest from the fermentor.

This is helpful thank you!

Very interesting that Kai's info is open source and Jamil's is not.

 

[kh54s10]

I use this calculator for my starters: http://www.yeastcalculator.com/

After working with it a few times it is quick and easy.

 

[rtt121]

Thanks gents. Both easy.

Question. Should the Growth factor progress in any correlation from Starter to starter to actual brew?

 

[Sadu]

888b cells is a lot if you are starting with under 100b from a smack pack.

Personally I consider this kind of stepping up way too much work. Instead I would brew a 1-2 gallon 1.050ish batch a week or 2 in advance of your 11 gallon brew. On brew day, you rack the little batch to secondary and steal 2-3 cups of yeast cake which should have your 888b healthy cells ready to go.

Personally I would brew all-grain and get nice beer from both batches but if you are short on time - brew using a hopped extract kit which you just add water to. Cheaper than DME, easier than fluffing around with decanting multi-step starters, gets you a good yeast cake that you can pitch to the big batch. You can either lager and drink the resulting small batch beer or throw it out.

 

[flars]

Thanks gents. Both easy.

Question. Should the Growth factor progress in any correlation from Starter to starter to actual brew?

Inoculation rate with viable yeast cells and starter size do correlate. You can inoculate a small starter with a huge number of yeast cells without getting many new cells produced. A growth factor of less than 1 is pretty much a waste of DME and time. The BrewUnited calculator will indicate an inappropriate starter size or inoculation rate.

 

[rtt121]

888b cells is a lot if you are starting with under 100b from a smack pack.

Personally I consider this kind of stepping up way too much work. Instead I would brew a 1-2 gallon 1.050ish batch a week or 2 in advance of your 11 gallon brew. On brew day, you rack the little batch to secondary and steal 2-3 cups of yeast cake which should have your 888b healthy cells ready to go.

Personally I would brew all-grain and get nice beer from both batches but if you are short on time - brew using a hopped extract kit which you just add water to. Cheaper than DME, easier than fluffing around with decanting multi-step starters, gets you a good yeast cake that you can pitch to the big batch. You can either lager and drink the resulting small batch beer or throw it out.

That is still just making a starter except you aren't stepping it up. I have been out of it in terms of homebrewing for awhile but I have in my head that that will not produce optimally performing yeast? Too high of a growth rate? Can anyone else chime in on this?

Using your thought I can even plug that into the calculators above and get the numbers: 1.050 4 liter starter with one smack pack gives 859 billion. Why wouldn't this be what these calculators recommend?

 

[rtt121]

Just found some evidence as to why I am thinking this. Per Mr. Malty faq.

Q: When increasing a starter in steps, should the steps be a certain size?
The size ratio of one step to the next can affect the health of the yeast and the amount of cell growth. A very large step can result in a change in yeast metabolism, where the sugars that are fermented last can fall out of favor with the yeast. The yeast become lazy and subsequent generations can become lower attenuating.

Is there any guideline as to what growth rate at any given step would be "too high" or is this just one of those things that has not really been tested.

 

[Sadu]

That is still just making a starter except you aren't stepping it up. I have been out of it in terms of homebrewing for awhile but I have in my head that that will not produce optimally performing yeast? Too high of a growth rate? Can anyone else chime in on this?

With all due respect, I think you may be overthinking this. Yeast slurry from previous batches is a fantastic resource for getting large volumes of healthy yeast. It's almost criminal to throw all that viable yeast away.

I definitely believe that looking after your yeast is important to brewing good beer. In my experience freshly harvested yeast performs every bit as good as a smack pack or a freshly made starter. The calculators are great for figuring out how much you need, but there is nothing wrong with that yeast if it's from a normal-gravity non-hoppy brew that had a healthy fermentation.

 

[rtt121]

With all due respect, I think you may be overthinking this. Yeast slurry from previous batches is a fantastic resource for getting large volumes of healthy yeast. It's almost criminal to throw all that viable yeast away.

I definitely believe that looking after your yeast is important to brewing good beer. In my experience freshly harvested yeast performs every bit as good as a smack pack or a freshly made starter. The calculators are great for figuring out how much you need, but there is nothing wrong with that yeast if it's from a normal-gravity non-hoppy brew that had a healthy fermentation.

Fair enough.

I always went by the montra. Healthy Yeast First. Cell Counts Second.

Your method seems to reverse the order so I will not be using it but it's probably just fine.

 

[jammin]

I quite using yeast calculators a long time ago. Here is a fantastic read that describes in a nutshell that cell counts are irrelevant. The only count that matter is the viable cell count. The best part is the dialogue about what a viable cell count means:

https://www.homebrewersassociation.org/forum/index.php?topic=20692.0