[KellerBrauer]

I’m not certain why I began thinking about this, but I’m hoping to find an answer nonetheless.  Many years ago, I had a kraeusen layer on my starter that actually blew the top off a 2,000 mL flask (the starter itself was about 1,300 mL).  However, it has never happened before or since.  In fact, I barely even get any foam at all.

Is it normal to NOT have a kraeusen layer in the starter?  And is there an explanation?

I add the DME (I use a light DME) to my regular tap water before the water boils to prevent boil flare up and I wait until my wort is cooled to 72 degrees F before adding the yeast.  I drop in my sanatized stir bar and away we go!  I typically pitch my starter between 24 and 28 hours after making. And I have solid fermentation activity in my beer within 12 hours after pitching the starter.

[Robert]

Funny you should mention it.  I've always assumed that you don't see a kräusen head on a starter for a couple of reasons.   One, it's such a small scale, quick fermentation. Either it's not enough activity to raise a big head or you just miss it.  But you'd see the "bathtub ring,"  wouldn't  you?  And on a stir plate,  you're continually knocking it down and  reincorporating it.   But there was one time for me, too... I was growing up some decidedly top cropping yeast from a bottle of commercial beer,  and that really did escape and ended up all over the place... I look forward to answers, too! 

[hopfenundmalz]

For me it depends on the yeast strain. 3787 and 1469 have huge krausens. Lager yeasts not so much.

[Richard]

I generally don't see any kräusen on my single-stage starters, although I have a couple of times. If I do a two-stage starter I usually see a pretty significant head of foam on the second stage even if I didn't see any on the first stage. I assumed it was a combination of more yeast and a smaller surface area as the flask is filled to the narrower part.

[RC]

I usually see a little foam on top of my (stirred) starters, but never a true krausen, as it doesn't have any yeast gunk in it. I think Robert is right about the stirring, which would prevent, or at least minimize, the accumulation of a true krausen in a stirred starter.

The only time I've ever had a true krausen on a stirred starter was when, overnight and unbeknownst to me, the starter stopped stirring, as the stir bar moved off the center of the flask bottom and was pinned against the side. So a krausen formed, and of course as soon as I moved the flask it gushed everywhere as the CO2 suddenly broke out of solution. Perhaps this happened that one time with you?

[Bob357]

Funny you should post this today. I put a starter on the stir plate yesterday and this morning it had more than 2" of krausen on it. I used Fermcap-S too. With probably over 100 starters under my belt, I don't remember ever seeing more than 1/4" before.

[KellerBrauer]

All great answers.  Thank you!  And it does make sense that the movement is preventing the kraeusen from building.

Bob - that’s funny!  You think the beer gods are trying to tell you something?

I too look forward to further input!

[goose]

I am going to weigh in on this as well.  I have always use a stir plate with my starters (sorry Denny that you can't find yours  ).   I make my starters the day before I plan to brew and always see a small amount of krausen on top of the wort after a few hours or so.  It falls back into the starter liquid overnight and I have a nice healthy cloudy starter the following morning as well as the proverbial "bathtub ring" Rob has mentioned.  Some people refrigerate their starters, decant the fermented beer, add chilled wort from their batch, and put it back on the stir plate.  I used to do this but now just pour the whole starter into the fermenter as it is more time efficient for me.

If I am using a really aggressive yeast, the krausen will sometimes get high enough to push the pre-sanitized sponge out of the flask.  I have resorted to using larger volume flasks to alleviate this problem.

[denny]

I am going to weigh in on this as well.  I have always use a stir plate with my starters (sorry Denny that you can't find yours  ).   I make my starters the day before I plan to brew and always see a small amount of krausen on top of the wort after a few hours or so.  It falls back into the starter liquid overnight and I have a nice healthy cloudy starter the following morning as well as the proverbial "bathtub ring" Rob has mentioned.  Some people refrigerate their starters, decant the fermented beer, add chilled wort from their batch, and put it back on the stir plate.  I used to do this but now just pour the whole starter into the fermenter as it is more time efficient for me.

If I am using a really aggressive yeast, the krausen will sometimes get high enough to push the pre-sanitized sponge out of the flask.  I have resorted to using larger volume flasks to alleviate this problem.

No reason to feel sorry for me, Goose...I'm happier without it!

[charlie]

That's interesting. I use mostly WLP-001 or WLP-007 and pitch a 500 ml stock starter into two 1L pitching starters in 2L flasks. These go on the stir plates, and I will have krausen within an hour or two. If I leave them on the stir plates overnight they will foam over, so I use the stir plates to control their fermentation rate, and turn them off when the krausen gets over 2/3 up the inside of the flask. The starters will usually finish out (little to no krausen) within 24 hours.

I have never encountered the situation that you describe!

Charlie

[KellerBrauer]

That's interesting. I use mostly WLP-001 or WLP-007 and pitch a 500 ml stock starter into two 1L pitching starters in 2L flasks. These go on the stir plates, and I will have krausen within an hour or two. If I leave them on the stir plates overnight they will foam over, so I use the stir plates to control their fermentation rate, and turn them off when the krausen gets over 2/3 up the inside of the flask. The starters will usually finish out (little to no krausen) within 24 hours.

I have never encountered the situation that you describe!

Charlie

That’s very interesting indeed.  Can you describe your exact process including the DME you use also, any yeast  nutrients, etc.?

[Robert]

That is curious indeed.   Since the very point of a stir plate is gas exchange, as well as deterring flocculation, it should (as in my experience)  prevent formation of a head.  I'm also curious about Charlie's procedure.   But whether I boil in the flask with Fermcap-S and use a stir plate, or just put separately prepared wort in a gallon jug and oxygenate,  I always use nutrient,  and have only the one time had significant (problematic) kräusen in a starter/ propagation.   I can't say strain,  even ale/lager, makes a difference  --  except that one time apparently.   BTW that one time, I was culturing from a bottle of SNPA.

[charlie]

That’s very interesting indeed.  Can you describe your exact process including the DME you use also, any yeast  nutrients, etc.?

All starters are 100 g/L Briess light dry DME (aprox 1.042 SG). I don't use any yeast nutrients or fermcap.

I prepare four 500ml stock starters from a yeast packet, and crash them when they finish out. Two days before I brew the pitching starters are prepared using 2L of fresh starter wort, and the 500ml stock starter is decanted and dispersed into them using the stir plate.

I don't have any experience using fermcap, but that might be why you don't get any krausen.

Charlie

[Richard]

Charlie is doing a two-stage starter. I see lots of kräusen if I do a second stage, too, but not usually in the first stage.

Charlie, when you make your 500 ml "stock starters" do you see kräusen in them, or only in the 2 liter "pitching starters"?

[Robert]

That’s very interesting indeed.  Can you describe your exact process including the DME you use also, any yeast  nutrients, etc.?

All starters are 100 g/L Briess light dry DME (aprox 1.042 SG). I don't use any yeast nutrients or fermcap.

I prepare four 500ml stock starters from a yeast packet, and crash them when they finish out. Two days before I brew the pitching starters are prepared using 2L of fresh starter wort, and the 500ml stock starter is decanted and dispersed into them using the stir plate.

I don't have any experience using fermcap, but that might be why you don't get any krausen.

Charlie

I only use the Fermcap when I  boil right in the flask.  When I do a larger starter, or second step,  I prepare the wort separately, usually without Fermcap, and pour it into a large jug, but still usually don't see much kräusen.   Except that one time....  I'm starting to suspect there's another factor here that's escaping us.

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