Over-flowing krausen in a 2000mL starter (stir plate)

male_ale · January 3, 2012, 2:12am

So, I am using a 2000mL flask for a 2000 mL starter using WLP099 (super high gravity yeast), on a stir plate.

I am two stepping the yeast in order to get one big ass starter for a big ass RIS (1.133 OG). I already did a 1500 mL starter, and it had little to no krausen. Now, today I decanted the beer on top and pitched a 2000 mL sized wort onto the yeast cake. This time WLP099 is going nuts. The krausen has pushed the foam stopper out on one side, and is slowly seeping out the side of it.

My question is this: Should I leave it how it is? Or do I throw a blow off onto it? I know blow-offs are usually a big no-no due to oxygen being unable to get to the swirling starter. Also, I figured the vacuum from the stir plate would suck up the star san as well. As a result, I just left it with part of the foam stopper covering the hole, and the krausen oozing out one side.

male_ale · January 3, 2012, 2:17am

Hah, just realized there’s a forum exclusively for yeast. Never even noticed it before, should have posted it in there…

scott_miller · January 3, 2012, 3:41am

Oh man. Got another sanitized flask that you could pour some out into?
Sanitized anything? You can just combine them later when things settle down.
I try not to get mine that full, and always use fermcap.

male_ale · January 3, 2012, 7:22am

I put a blow off on for it so I didn’t have to worry about it over night. I may lose a lot of yeasties, so I think that your idea of putting half into a gallon jug I have might be a better idea…

gruneun · January 3, 2012, 7:27pm

Wow, I’ve never had any noticeable krausen or surface activity on a stir plate, even in multiple step starters. I use a foam stopper, though, so I imagine it just allows it to breathe a bit easier.

dan_s · January 3, 2012, 9:48pm

+1 on using fermcap - the $2 you spend on a bottle goes a long way.

I brewed a maibock this morning for which I made a 2L starter that I stepped up with another 2L starter, after decanting. Like you, I had much more activity in the step up batch, but I’ve found that adding a drop of fermcap to the starter boil has always kept my starters from overflowing, even when making a 2L starter in a 2L flask on a stir plate, as I did earlier this week.

el_capitan · January 4, 2012, 2:39am

Fermcap all the way. Works in the boil kettle too, to knock down foam and prevent boil-overs. I’ve used it when making maple syrup for the same effect.

male_ale · January 4, 2012, 5:17am

@Gruneun: I use a foam stopper as well, just a crazy strain I guess.

I need to invest in some fermcap. Unfortunately, I don’t have a LHBS nearby where I could pick it up at. So, next big online order will have that included.

baratone_brewer · January 4, 2012, 9:16am

Can you use a 1gal glass jug with your stir plate?

tom_sawyer · January 4, 2012, 1:00pm

I’ve had krausen come out of my flasks many times, it makes a mess. It is very strai dependent, with Belgian and weizen yeasts being the most active. Fermcap helps, so does having a 4L flask or gallon jug for a 2L starter.