Krausen: in or out?

[BassBeer]

My latest batch (first AG! ) took off in about 4 hours and had monster krausen after about 12. The lid to my bucket was bulging so I popped on a 3/8" blowoff tube to relieve the pressure. It helped, but after a couple hours I checked on it and the tube was clogged so I washed it out and then the krausen started flowing pretty steadily. The lid was still bulging from the massive fermentation, and since I can only use a 3/8" tube with my bucket most of the krausen wasn't able to escape. Probably just enough to keep the lid from blowing. It's now subsided and I was able to throw on an airlock. I opened the lid to see the aftermath and it's the thickest krausen I've ever had! I'm talking almost the consistency of clay.

So my question is this: With a very vigorous fermentation where lots of krausen is produced, do you want most of the it to leave the beer, or can it fall back in without doing any harm? Does it matter either way from a flavor/clarity/final volume standpoint? Normally I'm not concerned because the fermentation isn't so vigorous but this time there was A LOT of it, and it really wanted to get out. I'm worried it will either cause my brew to be 1/2 trub, or have some other negative effect. Thanks in advance.

 

[jvanraay]

I've had the same issue many times. The "clay" looking stuff is yeast. I typically leave my beers 2-3 weeks in primary, no secondary, and don't have an issue. You may want to make sure that your fermentation temps aren't too high though. It does suck cleaning my fermenter afterwards. I'd soak your bucket as soon as you're done bottling/kegging. You'll appreciate next brew. Enjoy your brew!

 

[BassBeer]

Thanks for the response. The fermenter is at 59 degrees ambient temp, so I was really surprised to see such a vigorous fermentation for a 1.060 beer. My yeast starter apparently worked! But I doubt the internal temp ever exceeded 65F.

I thought I read somewhere that you want as much krausen to be blown off as possible, but I can't remember where, or if I actually read that. Does it matter more/less with certain yeast strains? Or not at all? Any input is appreciated.

 

[william_shakes_beer]

The krausen is material that you put in your beer. I cannot envision a situation where you would want to remove it. The hot break *should* have settled out and been removed as you strained your wort to the fermenter.

 

[DonLiguori]

Well, the krausen is the pale, creamy, foamy goodness on the top during fermentation, yeah? But on top of the krausen will form the clay that you're talking about, a dark-brown, non-foamy thin layer that floats up on the bubbles and coats the walls of the fermenter. In this layer you'll find all kinds of fusel oils and hang-over causing junk that you don't want in your beer. (This does not mean skimming it off avoids hang-overs, it can just take the edge off.) On the flip-side, if you're skimming off this layer, you're exposing the good stuff underneath to infection from airborne particles and/or whatever might have survived on your hopefully sanitized skimming utensil. People have also mentioned that alpha acids will hike a ride on the foam as well, so you're potentially de-bittering your brew by doing this. I had always let the junk fall back into the beer under the fear of contaminating it, but my last 5 batches I have cracked off the top and removed the junk during active fermentation. And they have been the best 5 batches of beer I've made in a long time. (To be fair, they are almost all new recipes I put together.)

So, it's really up to you. Should it be in the beer? Ideally, no. But neither should any of the contaminates you risk adding in the process of skimming the gunk off the krausen.