Lots of foam/Krausen on top of starter after 42 hours. Typical???

[timsch]

I started a 1.5 liter starter 42 hours ago from a vial of glycerine/WLP001 that I froze a few months ago. I've made a good number of starters before , but only in my 1000ml flask, never before in a 1 gallon jug, so I don't know if anything would be different with this setup. I've always had krausen build up and then fall to nothing within 24 hours using the flask and a 1 to 1.5 pint starter before. I used the proportions for the starter as calculated @ Yeast Calculator, using kai's option.

I've pulled off the foil and smelled it and it smells about as I'd expect from a starter. Sanitation was good.

Is this normal? I was going to pitch it this evening, but am 2nd guessing my timing.

 

[VikeMan]

Is that on some sort of stir plate? If so, I'd turn it off, wait a little while, then swirl and see if CO2 is still being produced.

 

[timsch]

Yes, it's on a stir plate. It spun the magnet off earlier this afternoon. There wasn't that much foam at that time I found it, but when I got it back on, the foam got particularly thick, as if the rest gave it that much more OOMPH when I got it stirring again.

 

[VikeMan]

Sounds like it still has some work to do.

 

[Vale71]

With the stir plate out of commission your starter beer absorbed CO2 up to the level dictated by the current temperature just like with a normal fermentation. Once you fixed the stir plate CO2 started coming out of solution creating the larger-than-usual Kräusen. One of the points of having a starter on a stir plate is to drive off CO2 as much as possible as it is toxic waste for yeast.