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General Category => General Homebrew Discussion => Topic started by: tomsawyer on January 13, 2011, 01:32:12 PM

Title: Swirling The Contents of Your Carboy
Post by: tomsawyer on January 13, 2011, 01:32:12 PM
I am a self-confessed yeast rouser.  When I see a lovely 4" krausen on a fermenting wort I just have to go rouse it by swirling the carboy.  I don't agitate wth caviation but the cicrcular action is enough to get the settled material off the bottom and moving.  I didn't used to be so moved to partake in this practice, but in switching from buckets to carboys I now have a great visual that triggers my OCD.

I know htat rousing yeast can be a technique for getting better attenuation in big beers, but do you think it has any negative (or positive) effects on an average beer? 
Title: Re: Swirling The Contents of Your Carboy
Post by: theDarkSide on January 13, 2011, 01:45:01 PM
I do this when I dry hop ( I dry hop right in the primary fermentor ).  Haven't noticed any bad side effects.
Title: Re: Swirling The Contents of Your Carboy
Post by: tumarkin on January 13, 2011, 02:03:06 PM
done gently, it shouldn't have any negative effects. some yeast need this type of attention more than others, but I don't believe it can hurt with any yeast. it can really help keep them going to achieve those last several points of attenuation or help avoid a stuck fermentation.
Title: Re: Swirling The Contents of Your Carboy
Post by: tygo on January 13, 2011, 02:28:07 PM
I agree that it shouldn't have any negative effects if done gently.  I just don't think there's much to be gained for an average beer.  Assuming you've got a healthy pitch of yeast they should be able to take care of the fermentation without the extra effort.

But try it.  Run a FFT on your beers and see if they get to the final gravity without rousing.  I'm guessing in most cases you'll find that they do and that'll save you from extra picking up of a full carboy  :D

With the big beers and more flocculant yeasts it may be worth the effort.
Title: Re: Swirling The Contents of Your Carboy
Post by: tumarkin on January 13, 2011, 04:04:35 PM
you don't have to expend the effort to pick up a full carboy.... in fact, I'd advise against it for safety reasons. I keep my carboys in plastic milk crates, so no danger of one hitting the other or hitting a hard floor & breaking. I just tilt the carboy up on edge slightly, and gently apply a circular motion. just a few gentle circles & that's enough to get some centrifigal action going.
Title: Re: Swirling The Contents of Your Carboy
Post by: phillamb168 on January 13, 2011, 04:20:01 PM
Run a FFT on your beers

Fast Fourier Transform?
Title: Re: Swirling The Contents of Your Carboy
Post by: denny on January 13, 2011, 04:23:03 PM
Run a FFT on your beers

Fast Fourier Transform?

Being an audio guy, that was my first thought, too!  But he meant fast ferment test.
Title: Re: Swirling The Contents of Your Carboy
Post by: redbeerman on January 13, 2011, 05:24:13 PM
WLP002 does not respond well to this type of stimulus.  It has a tendency to stick to the bottom of the fermenter and if you do rouse it, it over attenuates.
Title: Re: Swirling The Contents of Your Carboy
Post by: a10t2 on January 13, 2011, 05:33:05 PM
I know htat rousing yeast can be a technique for getting better attenuation in big beers, but do you think it has any negative (or positive) effects on an average beer?

I can tell you it isn't having any negative effects on your beers! I don't see how it could be a problem. Oxidation isn't a concern at that point. There are macro breweries that agitate continuously to speed up fermentation - actually, I have to do it to four tanks today. Stupid Colorado winter keeps crashing my beers...

Fast Fourier Transform?

My brain does that every single time. ::)

WLP002 does not respond well to this type of stimulus.  It has a tendency to stick to the bottom of the fermenter and if you do rouse it, it over attenuates.

Is that based on a controlled test? What is over-attenuation in this context? I don't doubt that agitation could reduce the FG, but when I hear "over attenuates" I think of a beer finishing drastically lower than anticipated.
Title: Re: Swirling The Contents of Your Carboy
Post by: redbeerman on January 13, 2011, 05:49:26 PM
I know htat rousing yeast can be a technique for getting better attenuation in big beers, but do you think it has any negative (or positive) effects on an average beer?

I can tell you it isn't having any negative effects on your beers! I don't see how it could be a problem. Oxidation isn't a concern at that point. There are macro breweries that agitate continuously to speed up fermentation - actually, I have to do it to four tanks today. Stupid Colorado winter keeps crashing my beers...

Fast Fourier Transform?

My brain does that every single time. ::)

WLP002 does not respond well to this type of stimulus.  It has a tendency to stick to the bottom of the fermenter and if you do rouse it, it over attenuates.

Is that based on a controlled test? What is over-attenuation in this context? I don't doubt that agitation could reduce the FG, but when I hear "over attenuates" I think of a beer finishing drastically lower than anticipated.

I have done bitters with WLP002 where one time I let the yeast finish without bothering it, another batch, same grist bill and mash, where I roused the yeast and the beer finished much drier, by about 6 points.  WLP002 is a fst fermenter and it flocs out like putty when left on its own.  It's the only yeast that I've used that has shown this type of behavior in lower gravity beers.