Evan!
Well-Known Member
Blow-offs and krausen size in general are constantly discussed around here, but I don't think I've ever seen the science behind it really explained. So, those of you who are a little more versed in the world of the biologic, help us out here. Why do some batches blow off or have very large krausen, while others have virtually none? I know some of it has to do with the yeast strain, but why? And why is there variation from one batch to the next with the same strain?
For example, I made a Rochefort 10 clone with the Wyeast Abbey II yeast, fresh from a smack pack with a big starter. It blew off like none other. I then reused that yeast cake for a Stone Vertical Epic clone, fully expecting it to do the same thing again (since yeast cakes have such a high cell count)...but, while the fermentation was vigorous and quick, the krausen never got to be more than 1/2" high. This is with the same yeast.
There seems to be no rhyme or reason behind krausen size. Whenever I'm expecting a blow-off, I don't get one. So, can we get to the meat of the science?
For example, I made a Rochefort 10 clone with the Wyeast Abbey II yeast, fresh from a smack pack with a big starter. It blew off like none other. I then reused that yeast cake for a Stone Vertical Epic clone, fully expecting it to do the same thing again (since yeast cakes have such a high cell count)...but, while the fermentation was vigorous and quick, the krausen never got to be more than 1/2" high. This is with the same yeast.
There seems to be no rhyme or reason behind krausen size. Whenever I'm expecting a blow-off, I don't get one. So, can we get to the meat of the science?