What is Krausen constituted of?

[r8rphan]

Is it just yeast? Yeast + hops? Trub? Yeast + trub? Martian feces?
What exactly is it (besides nasty tasting)?

 

[TheBaconator]

Per John Palmer;

"A head of foamy krausen will form on top of the beer. The foam consists of yeast and wort proteins and is a light creamy color, with islands of green-brown gunk that collect and tend to adhere to the sides of the fermentor. The gunk is composed of extraneous wort protein, hop resins, and dead yeast. These compounds are very bitter and if stirred back into the wort, would result in harsh aftertastes. Fortunately these compounds are relatively insoluble and are typically removed by adhering to the sides of the fermentor as the krausen subsides. Harsh aftertastes are rarely, if ever, a problem."

 

[r8rphan]

Thanks.. That explains why the stuff tastes so bad... sampled it once, and will never do it again.. was very hard to get the bitter aftertaste out of my mouth (took like three beers to do so)

 

[Pivzavod]

In Brewing With Wheat the author mentions that several breweries in Europe collect krausen from their beers to get rid of the "bitter" taste. They do this several times during active fermentation.

 

[Begin2Brew]

I saw a video of a brewery tour and the fermentor had a cutout in the side and the krausen was spilling into it and was washed out with a spray of water.