Stepping up to 350B cells

[rode_orm]

Hoping you guys can verify whether or not this yeast step up plan will work...

Knowns
-Brewing 5 gallons of 1.050 lager
-Need 350B cells to do the job
-Have a single lager smack pack dated 8/13 which should have 86B viable cells
-Equipment available is 2L Erlenmeyer flask and stir plate

The plan
Since I only have one smack pack and I don't have the equipment to do a big huge yeast starter, I think I have come up with a plan that should get me from 86B cells to 350B cells. However I have never stepped up a starter so this plan could be completely wrong for all I know

I figure a good first step is to get the 86B cells up to 200B. To get the 200B number using mrmalty.com I plugged in a bunch of OGs until it resulted in 200B in the yeast cells needed area. According to mrmalty, to do this I need to create a simple 1L starter with a stir plate. Seems simple enough.

The next step is based on some assumptions on my part which I am not sure are correct. So once I have 200B cells from my first stage, I now need to get them to grow to 350B cells. There is no clear way on mrmalty to tell it that you're starting with 200B cells, it assumes you have a regular smack pack. As such I manually set the viability to 200%, making it think I am starting with 200B cells.... could this actually work? If so, to get my needed 350B cells and starting from 200B, it tells me my stir plate starter should be 1.05L.

So here is the plan step by step....
1) create 1L stir plate starter, starting from 86B cells
2) let the starter go until it reaches 200B cells
3) cool and decant off most of the wort.
4) pour yeast into a sanitized temporary vessel
5) brew up a second 1.05L stir plate starter
6) pour the decanted 1st starter into it
7) let it ferment out
8) result in 350B cells....?

Thank You!

 

[rode_orm]

Hrmmm... brewersfriend.com doesn't seem to like this plan too much. Says "Starter is saturated. Increase starter size".

Back to the drawing board?

 

[TheJasonT]

What about splitting the first step of the starter? Roughly half then build it up, decant, store in a sanitized jar, repeat with the other half, then combine into one.

 

[bd2xu]

I use yeastcalc.com and it does a good job with step ups. However, it sounds like a 2L starter might get you there? I do 2L starters in 2L flask all the time... WITH fermcap-s, not without!

 

[bd2xu]

Actually 2L single step doesn't do it. Yeastcalc says a 1.5 and 1 will get you there

 

[rode_orm]

Cool site. Looks like this may work... .8L first step. 1.2L 2nd step.

 

[outside92129]

Kai wrote a good paper on stir plating yeast and his new formula can be found here:
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

2L and you're good to go. Yeastcalc.com also has incorporated his formula, in the dropdown choose "Stir Plate (K. Troester)"

the writeup/analysis:
http://braukaiser.com/blog/blog/2012/11/03/estimating-yeast-growth/

 

[austinb]

What about splitting the first step of the starter? Roughly half then build it up, decant, store in a sanitized jar, repeat with the other half, then combine into one.

A 2L starter would probably be the easiest way to do it but if you can't do that then this plan would probably work, just be extra careful with sanitation when working with yeast.