I’ve started top cropping yeast from my ales using a blow-off tube to move the krausen into a sterile jar. After two or three days, I’ve collected around 200ml of pure yeast, which is sitting under a liter of beer. My procedure has been to pour the beer off the yeast, add some distilled water, swirl and transfer to a clear jar.
This is all working fine, but I’ve noticed that when I taste the beer that was sitting on top of the yeast, it’s insanely bitter. I’d guess that along with the yeast and beer, hop residue is being pushed through the blow off tube.
My question is this: if the blow-off tube is removing bitterness from the beer, isn’t it obvious that the beer left in the fermenter is less bitter? If I were to use an airlock instead of a blow-off tube all all that hop residue would settle back into the beer, increasing the overall bitterness. Has anyone ever quantified the effect of removing krausen on the overall bitterness of the beer?
I actually did some testing on this years back. I found that removing the krausen had no effect on the perceived bitterness of the beer. Nor did it have any effect on beer quality. This was years ago in one of my earliest experiments. I should probably try it again with a little more rigorous procedure.
I’ve made three beers this way. The two I’ve tasted so far, a dry stout and an IPA, are some of my best beers yet. There’s a Scottish 80/- just about ready to keg that I’ve not tasted yet, but I have high hopes.
The interesting thing about the IPA is that I brewed it to 50 IBUs, which to my palette is very bitter, but the taste is much less assertive than I’d expected. I attributed this to the fact that I did FWH for the first time with this beer, but now I’m wondering if the bitter krausen removal had something to do with it.
Interesting process you bring up. Be careful in making this conclusion though. It is my understanding that when you use the FWH process, what you found is what is supposed to happen.
Therefore, I would be a bit careful in expounding that to the krausen process. Maybe isolate the factors?
I plan on doing this with a German Pils in the near future.
One is getting fermented in a 5 gallon corney and the blow off is goin out the keg in the air-lock jug
The other is going in a 6 gallon carboy fermented as usual letting the krausen fall prior to racking.
I’ve been speaking with someone about this (my bet he’ll chime in here soon) and he is leaning towards it making a difference on the smoothness of the bitterness.
If I had the dedication to the craft of someone like Kai, I’d be in my garage right now preparing 6 one gallon batches, each of which varied from the others on a single parameters. In three weeks I’d be comparing the results, creating excel spreadsheets and performing regression analysis on the results.
But I’m me, so I’ll just keep making beer and wondering why some is good and some is not.
I’m always aiming to blow off the kraeusen. Most of the German authors I have been reading are very ademate (spelling) about that. They say that Kraeusen that falls back into the beet can give it a harsh bitterness. But I haven’t found the opportunity to make a side by side yet. I may end up doing this as a small scale batch. Until
I can evaluate this process parameter more closely I stick with blowing off the gunk.
This is one of the cases where I want to have data to justify my process but there are other things that I’m interested in more and which I’d like to test first. Hence the lack of experimentation with this on my side.
I thought I was gonna be real cool and link to a Zymurgy story about this. THE IOWA BEER TINKERERS by Paul Ogg. Seems to be the type of experiment being discussed here. Dec 2004 Vol 27.
Maybe one of the Mods here can dig it up?
Bottom line was, blowing off the Krausen made a more enjoyable beer when tested side by side - but when drinking the retained krausen beer by itself it was also acceptable beer.
If I had the dedication to the craft of someone like Kai, I’d be in my garage right now preparing 6 one gallon batches, each of which varied from the others on a single parameters. In three weeks I’d be comparing the results, creating excel spreadsheets and performing regression analysis on the results.
But I’m me, so I’ll just keep making beer and wondering why some is good and some is not.
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I’m right there beside you. I’ll experiment with using different yeasts for the same batch of wort, but that’s as scientific as I get.
Based upon the data presented in Hombrewing Vol. 1 and a Brewing Techniques article where the IBU were measured bitterness is reduced when blowoff occurs.
Denny,
Can I just scan it and post it? Can’t see how it violates copyright if I take from AHA and post it on AHA.
I gotta say it’s not going to be a mind blowing experience to read this article, but it’s relevant.
