Step Starter Question

[sky4meplease]

I am making my first starter with Wyeast 2035 American Lager on a stir plate.

This is step one of a two step starter that will be cold crashed and decanted between steps and before pitching.

My question is when to cold crash step 1. Until this morning I had no activity in the flask but now have what looks like fermentation going on with bubbles rising.

Nothing I have read really says when it is ready only a time period for propagation (24-48 hours typically).

Are rising CO2 bubbles an indication that I let it sit too long? What should I be looking for?

 

[flars]

You will need about 18 hours, after active fermentation begins, for step one to complete. You could check the starter twelve hours, after active fermentation, by following these steps.
1. Turn off stir plate for two hours. 2. Give the flask a shake and swirl. 3. If no instant krausen, of any size forms, the starter may be complete.

 

[Stalevel]

Some of these lager yeasts are slower to start. CO2 bubbles are your indication that fermentation is active. Let it go. When all the sugar is consumed, the bubbles will stop and the yeast will begin to floc out (strain dependent, and your strain less so than say an english one). I usually try to give my 24 hrs after I see no activity.

To be fair, growth (big reason you'd use a starter) is complete well before fermentation is done. But, I wanna be sure I'm getting all the growth I can get.

 

[sky4meplease]

Sweet. Thanks for the advice.