Yeast starter, kräusen (or other visiable fermentation activity) or not?

Several times I've noticed Revvy say (as per the quote below) that he virtually never sees any kräusen or 'visible activity' in his yeast starters.

Revvy said:

As it is I've only ever seen two krausens actually on my starter, and the evidence of one on the flask at the "waterline" once. But I've never not had a starter take off.

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Obviously there is no right or wrong answer, a starter is to grow yeast and the amount of healthy viable and happy yeast you get at the end of the process is the most important thing.
But, I was still curious to see what everyone elses experience with their starters showing visible fermentation activity is.

Personally, I always get the yeast trying to crawl out of the top of the flask when making a starter. Usually I step up from small samples (often slants), the first few steps don't usually show much activity, but for me, the last (usually 2L) step is usually very active.

Here is the Wy1272 (24h after being stepped up from 400ml which was inoculated with about 1/4 of a Wyeast pack) on the stir plate yesterday:

As you can see the yeast is literally trying to escape the top of the flask by pushing up the aluminum foil.
The reason for the ugly (but practical) plastic tub is that stir-plate V1 worked great, until overflowing yeast shorted out the power supply.

And since I'm in no hurry (and spent the day planting hops) here it is now (48h after pitching), the kräusen has subsided so you can see the vortex from the stir-plate:

I'll put it in the fridge shortly to let it settle for a day or two before using it.

Here is the previous starter I made (stepped up from a slant):


Some of the yeast did escape this time, but this is it after spending a day in the fridge:


I have no idea what/why/how mine always like to crawl out of the top of the flask, but it's just what they always do for me.
Temps here have been about 15-20C so it's not too hot, and the starter wort was 1.030-1.040 usually made from wort 'saved' either from the kettle dregs or mash dregs from the previous brew, boiled and adjusted to the correct gravity.

I'm not able to check on my starters regularly so I often miss the actual krausen, but I've always seen the remnants of a krausen sticking to the sides of the flask. Just my experiences so far.

Although I usually have virtually no krausen, I have had a few recently that have behaved like yours. Mine were all white Labs, and I've only had this happen when starting straight from the vial.

-a.

Mine will behave like that when I add new wort to a starter that is already going. From what I understand that is exactly what you have been doing when this happens. I imagine it is something about adding a) new wort, and b) introducing more oxygen into the system, meaning another round of sexy time for the yeast.

Revvy says lots of things... it really depends on how you make your starter and how you handle it.

ArcaneXor said:

Revvy says lots of things... it really depends on how you make your starter and how you handle it.

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I was thinking it may also be related to how active the starter is stirred.
My smaller starters get stirred much more vigorously than the larger 2L ones, so maybe the yeast has more chance to ferment/kräusen if they are not stirred quite so much.

Mine don't do that, but I dont use a flask like that, I use an old fashion milk jug (I live in a town where you can still get milk delivered), so its much wider, so the yeast dont built up like that.

Other factors I think is the amount of yeast to start with (fewer = bigger krausen?) - and concentration of the wort.

I do one cup of DME in one liter of water.

I never have a krausen (at least that I've witnessed) on the stir plate. But I'll see evidence of fermentation usually- like "bubbly" liquid in the stir plate and a bit more yeast than I had before I started. At times, I've had to check the SG because I hadn't seen any hint of fermentation at all- and sure enough, the SG was down. So, sometimes I see activity, sometimes not.

For me, it's sometimes yes sometimes no.

A starter I made this week had a big head on it. But it was made from repitched slurry from a previous batch and was a decent amount of slurry, maybe 150 ml. It was super active. I'd say that my starters virtually always have some sign of fermentation on the beer line, some gunk or something when made from slurry. From a smack pack, sometimes I don't see krauesen. And, when the starter's going, I ALWAYS see Co2 bubbles rising up crazily as the stirplate kicks the Co2 out of solution, from either smackpack or slurry. I've literally seen this every single time I've used that stirplate for starters, which is around 25 times now I'd guess.