Stepping up a yeast starter?

[MattK]

I'm planning on doing a doppelbock soon, and I'm having some trouble figuring out how to step up my starter to get in the neighborhood of 545 billion cells (from Mr. Malty)

I only have a 2L erlenmeyer, and I'm wondering how I would go about stepping up from 1 vial of white labs to get enough yeast. I was looking at the yeast starter chart from Yeast, and it seems to indicate that if I want 545 billion cells, I will have to use a larger flask (a 5L). Can I get to where I need to be using just the 2L and stepping it up a few times? I know I'd be dealing with diminishing returns at some point, but I'm just not sure if I can get to where I want to be with the equipment I currently have.

I don't currently have a stir plate, so I'd just be using intermittent shaking.

Any thoughts on how I could do this, or how many times I'd need to step up my 2L to get the proper sized pitch?

[brewinhard]

I have always found stepping up yeast starters to be a pain in the ass. I almost feel that for the time I spend doing the different steps (boiling, cooling, pitching, tending to it, etc) I am just better off brewing a lower gravity lager to get enough yeast to pitch into my higher gravity beers.

For example, a couple mos ago I brewed a 1.050 munich helles and used the yeast cake to ferment a 1.091 Dopplebock. The bock took 5 weeks in primary at 49F just to ferment completely and that was even racking onto the fresh yeast cake. Then you get at least an extra beer from the purchase of your yeast. You could even do several low gravity beers first, then use the final yeast cake to ferment a big daddy.

I am sure there is a way to use just a 2 L flask to get your cell count high enough. Hopefully someone with some handy experience doing so will chime in. Otherwise, I would just brew a small gravity beer and you will definitely have enough yeast then.

[spiderwrangler]

If you only have a single 2L flask, it's hard. If you were to decant off, add fresh wort and ferment out, you'd probably only get another 1 fold increase. If you do that again, you might get another 0.5 fold increase... the diminishing returns you talked about. Also in order to do that, you are potentially looking at weeks worth of starter making. If you figure you're doubling each time you go from vial into a 2L starter, if you had more flasks you could do one starter, decant and split it between two flasks, you'd end up with a 4x increase...
Or you could go from your 2L flask into a gallon growler and get about the same increase...

Basically what the other poster said is my take on things... if you need to step it up a huge amount, you're probably better off getting a smaller beer going first, then harvest the yeast from that (Though you may think of rinsing the yeast first).

[28paws]

The way I did it with only one flask was to start out with 800 mls for 24 hours rousing every time I walked by. Then sterilize a big mason jar and lid in star san, then use it to hold your starter while you boil and cool another 1000 mls of starter wort.
Then just add it back to your flask.

Cheers

[scotchpine]

Either way, I would suggest buying or building a stir plate. I have much had healthier starters since I have been using mine.