Author Topic: Great attenuation.....a little too great  (Read 4331 times)

Offline DrewG

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Re: Great attenuation.....a little too great
« Reply #15 on: October 12, 2012, 08:44:56 AM »
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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.


Also:
Pitched at 64f
Aerated with pure 02 for one minute at medium flow (i dont have a meter)
Fermented at 68, with a D-rest after 72 hours up to 71
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Online denny

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Re: Great attenuation.....a little too great
« Reply #16 on: October 12, 2012, 09:59:03 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.

There's an audio recording there, too, if that would help.
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Re: Great attenuation.....a little too great
« Reply #17 on: October 12, 2012, 10:00:26 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.

Greg said during the presentation that he hopes to do more work with this to confirm and expand his initial findings.
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