I want to make a yeast starter for a lager. I even went out and got a 3000 ml Erlenmyer Flask. According to mrmalty.com's calculator I need 506 Billion cells. With the two vials of White Labs yeast it says I need 3.34 Liters of wort.
1)I've searched but can't seem to find clear instructions on stepping up a starter. I understand the procedure, but what wort volumes would I need to have for a two step starter? OR 2) should I just do this starter in a growler and leave my new erlenmyer flask sitting in the box until next time?

3 Answers 3


Here is a link to a NB document that outlines how to use one and two stage yeast starter. There are some lengthy equations that can easily be entered into a spreadsheet for easy calculation. It will also give you the different rates when using a stir plate.

  • Sweet. I DO have a stir plate (from NB). But based on mrmalty I bought 2 viles of White Labs. How can I figure the effects of 2 viles in the starter?
    – Bill Goetz
    Commented Jan 22, 2011 at 2:34
  • I would guess that the final number would be a little less that double the amount if using only one pack. Commented Jan 24, 2011 at 17:17

Assuming you are using his pitching rate calculator, here is what I would suggest: Switch it from "Simple Starter" to either "Simple Starter with O2 at Start" or "Simple Starter with Intermittent Shaking."

O2 at Start basically means you shake it up really well when you start the fermentation of the starter (or if you add oxygen via diffusion stone).

Intermittent Shaking means you will shake up the starter whenever it is convenient for you to do so--usually every couple of hours.

You'll get a lot more yeast by shaking rather than just letting the flask sit there on its own, and you'll need far less starter.

If you already did this and do need to step up a starter, here's how:

  • Make your yeast starter at the full volume of your flask
  • Wait until it seems to have stopped fermenting significantly (12 hours to 3 days depending on the viability on the yeast, oxygen, and other conditions)
  • Put the flask in the fridge until most of the yeast has settled into a cake at the bottom of the flask
  • Decant the liquid from atop the yeast cake by slowly pouring it out
  • Add new wort and let that build up

Ultimately, I would highly recommend picking up a stir plate for your yeast starters--you'll be able to build up even more yeast with less wort and liquid vials. I purchased mine for cheap at a place called Brewers Hardware ($44). http://www.brewershardware.com/Brewers-Hardware-Stir-Plate.html

  • Whoops, I shoulda said, I do have a stir plate.
    – Bill Goetz
    Commented Jan 22, 2011 at 2:35

This seems like an appropriate place to drop a link to a well produced, if not slightly awkward :), instructional video http://www.youtube.com/watch?v=SMQ1L9iVvz4 that walks you through the starter process.

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