2 step starter with only one flask

[SadDog]

I am planning on brewing up a lager soon and I know I will need to do at least a 2 step starter. My problem is that I only have one 2 L flask.

My question is what is the best way to do a multi-step starter with only 1 flask? Should I do a normal 2L starter (with 1 vial of yeast), decant and just add another 2L of wort? My goal is to get to about 400B cells but can I do it with just one 2L flask or do I need actually increase the volume?

 

[progmac]

the calculator at yeastcalc.com is great for this

i have adequately pitched a lager with a 2L starter in one vessel stepped up by 1L increments. Or you can do as you describe

 

[jperry]

When stepping up a starter, I remember hearing somewhere on here, that you want to double the amount of the wort. Im not sure of the reason, behind this process, but it deals with the growth rate of the yeast. For Example, If you begin with a 1L starter, then step up to a 2L starter. Using the yeast calc., you can get it done with a stirplate. However, if your 2L flask is not large enough to fit comfortably, then consider using a one gallon jug/growler. I got one at my LHBS for around 6 bucks.

 

[Paradigm]

My biggest issue is that my stirplate isn't "rated" for things bigger than 2L flasks

 

[LLBeanJ]

My biggest issue is that my stirplate isn't "rated" for things bigger than 2L flasks

That doesn't mean it won't work with bigger flasks. I believe my stir plate is only designed for 2L flasks, but I've run many a starter using my 5L flask on that stir plate. It does just fine.

 

[jbaysurfer]

I am planning on brewing up a lager soon and I know I will need to do at least a 2 step starter. My problem is that I only have one 2 L flask.

My question is what is the best way to do a multi-step starter with only 1 flask? Should I do a normal 2L starter (with 1 vial of yeast), decant and just add another 2L of wort? My goal is to get to about 400B cells but can I do it with just one 2L flask or do I need actually increase the volume?

I think you can get 400B cells in a 2L flask with a step up...easily.

I'd do it exactly as you mention. First step, crash and decant, 2nd step, crash, decant, pitch.

Edit: I haven't run it through a calculator, but another option is to do a 750ml starter in your 2L flask, then feed the yeast with another 1.25L of starter wort after the first step is done reproducing (2 day with a stirplate).

I use one single drop of fermcap when maxing out my flasks to prevent blowover.