I made a 2L starter with 2 Wyeast 1056 smack packs, yeast nutrient, a shot of O2 at the beginning and intermittent shaking. Last night it was going strong and this morning it had a nice high krausen.

Then I went to work and came home to find that it went nuts. It wasn't much, but there was a nice little puddle of yeast next to the flask. I've learned my lesson to use larger than a 2L flask for a 2L starter.

My questions are:

Did I lose too much yeast?

I'm not brewing until tomorrow morning so will there be enough reproduction of yeast cells by then to replace the lost yeast?

Or, should I just not worry and pitch it like planned?

3 Answers 3


Two packs in 2L was probably overkill save yourself a pack and put one in 2L next time. The active blowoff helps keeps things from falling into the starter once it gets going, much like an open fermentor does as well. The dropping pH of the starter helps keep things bacteria-static as well. Bacteria might get in there but they won't multiply much in that environment.

  • 1
    I needed 2 packs because it was for a big beer with a gravity of 1.095 and I didn't have time to do a step starter so I went with more yeast to start with to reach my desired amount.
    – HopHead73
    Apr 28, 2012 at 23:45
  • 1
    2 packs into 2L is a lot regardless of OG, I'd do closer to 3L for that.
    – brewchez
    Apr 29, 2012 at 16:09

As long as your starter was not exposed to contamination i think you are good just pitching as planed.

  • 2
    the high concentration of yeast will fend off any other microbes, so the risk of infection is low. sound like you got a good healthy starter.
    – mdma
    Apr 28, 2012 at 9:08
  • That's what I figured, but I always just like a little reassurance. This thing is a beast, 36hrs later and still good activity and huge head. They better be ready cause they are going into a 1.096 DIPA today
    – HopHead73
    Apr 28, 2012 at 11:21
  • I don't know if yeast themselves fend of other microbes, but the process of fermentation and the off gassing CO2 helps keep things from getting in there.
    – brewchez
    Apr 28, 2012 at 22:06
  • the yeast themselves don't specifically attack microbes, but rather they create a hostile environment for aerobic organisms, and one that is too acidic and alcoholic for most bacteria to thrive in.
    – mdma
    Apr 29, 2012 at 7:06

You have more than enough yeast unless you plan to brew more than 20 gallons. The net flow of foam outward was probably sufficient to expel any airborne bacteria.

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