Author Topic: Great attenuation.....a little too great  (Read 3945 times)

Offline DrewG

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Great attenuation.....a little too great
« on: October 11, 2012, 07:07:05 AM »
Brewed an ESB a while back, racked it to a keg last night and checked the FG, which was 1.008 (expecting around 1.014). Fullers strain, 1.5L starter pitched at 18 hours. With an SG of 1.059, that's approx 87% attenuation and 6.8% ABV....

I've used 002 a fair amount and never had it go this low. The beer tasted clean, a touch boozy but it's green yet. Zero off flavors I can detect, anyway. Decent mouthfeel, didn't seem overly dry.

I'm not sure where to start, my refractometer, hydrometer or all of my thermometers. I mashed at 154, but even if I was off by 10 degrees low, I wouldnt think 002 would go 87%. My beers all attenuate well, but somethins funky here.
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Offline davidgzach

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Re: Great attenuation.....a little too great
« Reply #1 on: October 11, 2012, 07:10:01 AM »
Definitely check everything, but I've had some wierd attenuations in the past with nothing to point my finger at except the yeast.  Sometimes they just decide to change the game....

Dave
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Offline Kaiser

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Re: Great attenuation.....a little too great
« Reply #2 on: October 11, 2012, 07:30:42 AM »
Wlp002 can even go 100% if you feed it only sugar.

The yeast attenuation values are meaningless if you don't know how they were gathered.

I guess you wort was more fermentable than expected.

Kai

Offline DrewG

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Re: Great attenuation.....a little too great
« Reply #3 on: October 11, 2012, 07:38:33 AM »
Looking at my notes, and I ended up using a blowff on this beer, which I've never needed with 002.

The grist was:

12 lbs maris otter
8 oz c-15
4 oz c-120

Mash temp was 154, 1.5 qt/g.

Nothing out of the ordinary.

The last 3 beers I used 002 for:

Special bitter: 78% attenuation
Souther English Brown, two times: 67% and 66.7%
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Re: Great attenuation.....a little too great
« Reply #4 on: October 11, 2012, 07:47:14 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

for smaller beers that I want to maintain a lot of body in I like to mash at 162 or so. in the 1.030-1.040 range I can get a beer to finish at 1.014 with this mash temp and a little medium crystal (L45 maybe)
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Offline troybinso

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Re: Great attenuation.....a little too great
« Reply #5 on: October 11, 2012, 07:47:27 AM »
Yeah, that is strange. Every time I have used that used I tend to get no higher than mid 70's for attenuation. And when it is a split batch with another yeast - say WY1056, the WL002 always ends up a couple of points higher for final gravity. 

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Re: Great attenuation.....a little too great
« Reply #6 on: October 11, 2012, 08:49:59 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

Yep, from Greg Doss of Wyeast.  AHA members can access it here.....

http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-04%20Attenuation%20-%20Gregg%20Doss.pdf
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Re: Great attenuation.....a little too great
« Reply #7 on: October 11, 2012, 09:51:15 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

Yep, from Greg Doss of Wyeast.  AHA members can access it here.....

http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-04%20Attenuation%20-%20Gregg%20Doss.pdf

I just experimented with this on a barley wine I brewed this weekend. I don't have a side by side but I have brewed this recipe more or less a couple times and have notes I can compare to about terminal gravity at least. not a lot of variables as the grist is just 25 lb munich.
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Re: Great attenuation.....a little too great
« Reply #8 on: October 11, 2012, 09:53:35 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

Yep, from Greg Doss of Wyeast.  AHA members can access it here.....

http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-04%20Attenuation%20-%20Gregg%20Doss.pdf

I just experimented with this on a barley wine I brewed this weekend. I don't have a side by side but I have brewed this recipe more or less a couple times and have notes I can compare to about terminal gravity at least. not a lot of variables as the grist is just 25 lb munich.

Have you read through Greg's entire presentation?  There's a lot of valuable info there.
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Re: Great attenuation.....a little too great
« Reply #9 on: October 11, 2012, 09:54:41 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

Yep, from Greg Doss of Wyeast.  AHA members can access it here.....

http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-04%20Attenuation%20-%20Gregg%20Doss.pdf

I just experimented with this on a barley wine I brewed this weekend. I don't have a side by side but I have brewed this recipe more or less a couple times and have notes I can compare to about terminal gravity at least. not a lot of variables as the grist is just 25 lb munich.

Have you read through Greg's entire presentation?  There's a lot of valuable info there.

I haven't. I will tonight though.
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Offline DrewG

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Re: Great attenuation.....a little too great
« Reply #10 on: October 11, 2012, 12:33:04 PM »
From Neva Parker:

"Its actually capable of good attenuation if you can keep it in suspension. That's a lot of the challenge with a strain like that, which is what normally makes it less attenuating. Hope that helps!"
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Offline davidgzach

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Re: Great attenuation.....a little too great
« Reply #11 on: October 12, 2012, 06:00:53 AM »
Wasn't there a presentation at NHC (i wasn't there but I think Denny mentioned it) that indicated a mash temp of 153 was optimal for attenuation. If you were at 154 you were right on that threshold.

Yep, from Greg Doss of Wyeast.  AHA members can access it here.....

http://www.homebrewersassociation.org/attachments/presentations/pdf/2012/1616-04%20Attenuation%20-%20Gregg%20Doss.pdf

Thanks for posting.  Good info.

Dave
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Offline troybinso

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Re: Great attenuation.....a little too great
« Reply #12 on: October 12, 2012, 07:09:29 AM »
I just read through that presentation. Pretty cool stuff, but a bit confusing at times with just the slides. It would be neat if someone could make up a calculator using his percentages for each of the factors for terminal gravity.

Yeast strain, grist, mash temp and mash time. DrewG, if you have accurate measurements for these four things, we could see how it compares to Doss's presentation.

Offline DrewG

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Re: Great attenuation.....a little too great
« Reply #13 on: October 12, 2012, 08:17:00 AM »
Quote
Yeast strain, grist, mash temp and mash time. DrewG, if you have accurate measurements for these four things, we could see how it compares to Doss's presentation

I do:

WLP002 (I don't have the empty vial in front of me, but if I remember correctly the viability was 80 or 85% when I plugged it into JZ's yeast calculator) 1.4 liter starter @ 1.035. Stirplate for 18 hours. Direct pitch, no cold crash. Normally I would have decanted but I didnt have time on this one.

12 lbs maris otter
8 oz c-15
4 oz c-120

Mash temp target was 154, 1.5 qt/g.
I missed low at 151, added approx 2 quarts boiling water and raised to 153.5 (so it was at 151 for 10 minutes tops) for 1 hour. 





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Offline erockrph

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Re: Great attenuation.....a little too great
« Reply #14 on: October 12, 2012, 08:34:58 AM »
I just read through that presentation. Pretty cool stuff, but a bit confusing at times with just the slides. It would be neat if someone could make up a calculator using his percentages for each of the factors for terminal gravity.

I think his experiments are fantastic and provide a lot of food for thought, but I'd hesitate to try to extrapolate his results empirically just yet. What if certain yeast strains are better/worse at fermenting Crystal malt? Or maybe certain strains handle higher or lower mash temps better than others.

I think the trends that Greg discovered are my biggest takeaways from this presentation. I think there are too many variables to try to pin down an exact FG in advance, but this will definitely help make some choices about things like mash temp, amount of adjuncts/specialty grains and yeast selection when tweaking recipes.
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