Author Topic: Stirring the fermenter  (Read 1269 times)

Offline DrGMG

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Stirring the fermenter
« on: June 23, 2016, 04:08:08 PM »
I bought this stir plate

http://www.northernbrewer.com/maelstrom-stir-plate

In the video it has a 5gal fermenter filled with water and it creates a very nice vortex.

My question, would using it in the first 2-3 days after pitching increase the rate of fermentation? would there be any bad/good side effects?
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Offline denny

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Re: Stirring the fermenter
« Reply #1 on: June 23, 2016, 04:19:29 PM »
I bought this stir plate

http://www.northernbrewer.com/maelstrom-stir-plate

In the video it has a 5gal fermenter filled with water and it creates a very nice vortex.

My question, would using it in the first 2-3 days after pitching increase the rate of fermentation? would there be any bad/good side effects?

I really doubt it would increase the rate of fermentation.  The yeast at that point is very active and pretty much keeps itself in suspension.  A possible drawback could be oxidizing your beer. 
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Offline brewinhard

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Re: Stirring the fermenter
« Reply #2 on: June 23, 2016, 04:59:43 PM »
I bought this stir plate

http://www.northernbrewer.com/maelstrom-stir-plate

In the video it has a 5gal fermenter filled with water and it creates a very nice vortex.

My question, would using it in the first 2-3 days after pitching increase the rate of fermentation? would there be any bad/good side effects?
  A possible drawback could be oxidizing your beer.

This ^^^^^. After yeast have absorbed all the initial O2 they require your beer could oxidize.

Offline DrGMG

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Re: Stirring the fermenter
« Reply #3 on: June 23, 2016, 05:18:29 PM »
Good point.

Thanks.
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Offline narvin

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Re: Stirring the fermenter
« Reply #4 on: June 23, 2016, 05:54:53 PM »
If you wanted to make a beer that required daily oxygenation (i.e. with Ringwood) this could help.

With a Peter Austin system, they not only perform open fermentations with Ringwood but also rouse and aerate daily.

Or it could also be useful in a super high gravity beer.  But I agree that "regular" beers don't need it.
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Offline denny

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Re: Stirring the fermenter
« Reply #5 on: June 23, 2016, 06:26:39 PM »
If you wanted to make a beer that required daily oxygenation (i.e. with Ringwood) this could help.

With a Peter Austin system, they not only perform open fermentations with Ringwood but also rouse and aerate daily.

Or it could also be useful in a super high gravity beer.  But I agree that "regular" beers don't need it.

You need to define "super high gravity".  I've made beers up to around 1.120 using "normal" techniques and they turned out fine.  I can't see any advantage to this over occasional rousing.
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Offline narvin

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Re: Stirring the fermenter
« Reply #6 on: June 23, 2016, 06:44:11 PM »
If you wanted to make a beer that required daily oxygenation (i.e. with Ringwood) this could help.

With a Peter Austin system, they not only perform open fermentations with Ringwood but also rouse and aerate daily.

Or it could also be useful in a super high gravity beer.  But I agree that "regular" beers don't need it.

You need to define "super high gravity".  I've made beers up to around 1.120 using "normal" techniques and they turned out fine.  I can't see any advantage to this over occasional rousing.

Well, I was thinking of an 18%+ beer.  I hear incremental feedings and aeration help.  But I've never felt like I wanted to make one so I haven't tried any of the tricks.
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Offline Stevie

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Re: Stirring the fermenter
« Reply #7 on: June 23, 2016, 06:49:13 PM »
Well, I was thinking of an 18%+ beer.  I hear incremental feedings and aeration help.  But I've never felt like I wanted to make one so I haven't tried any of the tricks.
There is an episode of the Jamil Show where Sean Paxton discussed doing this for a DFH 120 clone. He mentioned the only reason he did it was because having a conical made it easy to pull off some beer to add sugar to. Sounds like a complete PIA, but I do want to try it sometime.

Offline erockrph

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Re: Stirring the fermenter
« Reply #8 on: June 23, 2016, 06:55:22 PM »
The thing is, you never really know when the yeast are done with their growth phase. I think you'd run a much bigger chance of oxidation by continuous aeration rather than a one-time shot of oxygen. For a big beer, I'd rather hit it with a 2nd dose of oxygen about 18-30 hours after pitching. I've had good results up to 1.142 O.G. with this.
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Offline denny

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Re: Stirring the fermenter
« Reply #9 on: June 23, 2016, 06:56:46 PM »
The thing is, you never really know when the yeast are done with their growth phase. I think you'd run a much bigger chance of oxidation by continuous aeration rather than a one-time shot of oxygen. For a big beer, I'd rather hit it with a 2nd dose of oxygen about 18-30 hours after pitching. I've had good results up to 1.142 O.G. with this.

Totally agreed
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Offline blair.streit

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Re: Stirring the fermenter
« Reply #10 on: June 23, 2016, 09:23:32 PM »
I'd also add that there has been discussion in other threads about the shearing force caused by stirplates exerting some stress on the yeast that can cause off flavors. My paraphrasing may be inadequate, but my take-away was that stirplate-made starters yield off-flavored starter beer. Most people making stirplate starters have no issues if they decant or repitch that liquid into a "standard" fermentation (where ostensibly the yeast could clean up some of the damage). However, if you were applying the stirplate to the full beer, it seems you would be susceptible to the same off-flavors.

Setting aside the debate about the source of those flavors, I'm comfortable saying that I want my beers to taste better than my stirplate starters did, so I would be a little gunshy about this myself.

Offline DrGMG

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Re: Stirring the fermenter
« Reply #11 on: June 23, 2016, 10:31:55 PM »
The thing is, you never really know when the yeast are done with their growth phase. I think you'd run a much bigger chance of oxidation by continuous aeration rather than a one-time shot of oxygen. For a big beer, I'd rather hit it with a 2nd dose of oxygen about 18-30 hours after pitching. I've had good results up to 1.142 O.G. with this.

How do you do this? I'll be making a Dark Lord clone and its kinda big.
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Offline erockrph

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Re: Stirring the fermenter
« Reply #12 on: June 24, 2016, 02:54:30 AM »
The thing is, you never really know when the yeast are done with their growth phase. I think you'd run a much bigger chance of oxidation by continuous aeration rather than a one-time shot of oxygen. For a big beer, I'd rather hit it with a 2nd dose of oxygen about 18-30 hours after pitching. I've had good results up to 1.142 O.G. with this.

How do you do this? I'll be making a Dark Lord clone and its kinda big.
The key is a big, healthy pitch of yeast that has been acclimated to a higher abv. I usually brew a 1.040 beer as a starter, use some of that slurry into a beer in the 1.060-1.065 range, then use the full yeast cake from that beer in the big beer. Oxygenate well, and hit it with a second, smaller dose of O2 about 24 hours after pitching. I got a 100% Maris Otter barleywine (no sugar added) from 1.142 down to 1.024 by doing this.
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Offline narvin

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Re: Stirring the fermenter
« Reply #13 on: June 24, 2016, 03:18:48 AM »
I'd also add that there has been discussion in other threads about the shearing force caused by stirplates exerting some stress on the yeast that can cause off flavors. My paraphrasing may be inadequate, but my take-away was that stirplate-made starters yield off-flavored starter beer. Most people making stirplate starters have no issues if they decant or repitch that liquid into a "standard" fermentation (where ostensibly the yeast could clean up some of the damage). However, if you were applying the stirplate to the full beer, it seems you would be susceptible to the same off-flavors.



You have to spin it like a cyclone to even hit this in theory.  In practice, it doesn't happen.  Starters smell a bit estery because they are fermented warm.

I needed a big pitch for my last lager so I did two 1 gallon jugs, one on the stir plate and the other without but substituting a minute of pure O2 at the start.  It was the O2 started that smelled odd, not just oxidized but a bit harsh and phenolic.  The stir plate was fine.

At any rate, I don't think you'd get any positive effects from using it on a fermenting beer, but you probably won't see any negative ones either for the first few days.  I still think it would be interesting to try with Ringwood.
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Offline blair.streit

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Stirring the fermenter
« Reply #14 on: June 24, 2016, 12:20:03 PM »
You have to spin it like a cyclone to even hit this in theory.  In practice, it doesn't happen.  Starters smell a bit estery because they are fermented warm.
I initially thought my bad tasting starters were caused by growing lager yeast at high temp. Then I did a run of about 6 stir plate starters in my fermentation fridge at 60F and all of them had the same issue.

I've done the same 60F routine with a couple of SnS starters using O2 to foam, and they just taste like thin, sugary malt-water (which is what I would expect).

I do have a lab stir plate from the 60's and a penchant for cranking it up until I create a vortex of doom. I'd like do do some more experiments to try to isolate what changed, but the new technique has been working well for me so I lost interest.

Anyway, as it relates to this topic I guess all I can say is that I've had experience that's made me leery of potential off flavors that could be caused by stir plates, especially if used in a beer rather than a starter. YMMV