Lager Yeast Starter

So i'm preparing for an Oktoberfest beer and had some questions regarding my starter.

I've got a 4 liter starter using White Labs WLP820 Oktoberfest yeast. It has been on a stir plate at 50 degrees for the last 7 days. The thing that concerns me is that there is no Krausen in the starter. It looks yeasty, smells yeasty but there is nothing on the surface.

This is my first lager starter so I don't know if that is normal or not.

It's normal. First off, lager yeast is bottom fermenting and doesn't always create the same head of foam as ale yeast does. Second, on a stir plate, you'll seldom see an actual krausen form as the wort/beer is swirling. Sounds like every thing's going smoothly.

Thanks for the info. That makes me feel a little bit better.

How do I know when to crash the yeast if I don't see anything to indicate fermentation has completed? I'm using a foil cover over a flask in a sanitized edgestar kegerator so that rules out checking the airlock for activity.

You should use a hydrometer to determine when fermentation is happening, when to do a diacetyl rest if you choose to do one, and when the beer is complete.

I was referring to the yeast starter but now that i'm drinking about it, I could take a Refractometer reading which would require just a few drops from a glass pipet. Since i'm only concerned about end of fermentation, accuracy would not be an issue here.

Thoughts?

WesP said:

Thanks for the info. That makes me feel a little bit better.

How do I know when to crash the yeast if I don't see anything to indicate fermentation has completed? I'm using a foil cover over a flask in a sanitized edgestar kegerator so that rules out checking the airlock for activity.

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Give it ~36-48 hours on the plate. When you shut it off, you should get a nice layer of yeast at the bottom.

It's probably done but you should check to make sure.

Next time ferment your starter at room temperature; it'll be done sooner and won't have any ill effects on your yeast's ability to ferment the main batch.

osagedr said:

Next time ferment your starter at room temperature; it'll be done sooner and won't have any ill effects on your yeast's ability to ferment the main batch.

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+1 for sure. I never temp control any of my starters, simply ferment them out, cold crash, decant the "beer" and pitch the slurry.

I read someplace that doing a warm starter for a lager yeast might cause unwanted mutations and get the yeast used to a warm environment rather then a cold environment.

Could there be ANY noticeable difference in flavor of beer if a lager warm was started warm rather then cold?