catalanotte
Well-Known Member
- Joined
- Jul 30, 2014
- Messages
- 324
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Looking for some help here with a very stuck fermentation. Made an 10 gal all grain batch of Alt a week ago (1.053 OG, target 1.013 FG). Had a strong start for a few days, then tapered of and quit at about day 5. 3 days of steady 1.030 readings (corrected refractometer, that's not it). I have been brewing for a long time and haven't seen a stuck fermentation like this in a very long time.
Fermentability - No reason to believe that wort is not fermentable, good mash/sparge.
Good water (RO blend) Ca 93.5 Mg 20.3 Na 11.8 Cl 85.4 SO4 65.4 HCO 55.302 with some additional lactic acid in mash and sparge for pH control. Good mash pH 5.45, step mashed at 145/156/168 with complete conversion based on iodine, good temperature calibration. Started mash with a 1qt/lb infusion, stepped up to 1.6 qt/lb with second add, decoction for mash out. Grain bill roughly 60% pils, 30% munich, 9 % cara, and 1% carafa. Better than expected mash/sparge efficiency, made some adjustments to hit target OG of 1.053.
Yeast Health - Pitched about 350 B cells or .65 B/ml/deg P and aerated wort with a good shake (normal process again, always works)
4L starter made with a fresh pouch of Wyeast 1007 and a bit of nutrient, ran for 2 days until completely finished, and mostly cleared. Starter should have produced ~350B cells for 10 gal batch with starter build, this is about .65 B/ml/deg P. A bit under the .75 that many use, but this is max I can get with a one step starter and have good history with this pitch level for ales under 1.060. Might step this up to min .75 next time as a precaution. Decanted (clear spent wort, good yeast cake in bottom of starter) and pitched at 68 deg then dropped to 64 for fermentation. Wort was well aerated by a good shake in the fermenter.
Equipment/Process Changes - Only recent change to process/equipment is the new use of large RO dilutions for alkalinity reduction, used to use lime treated water which resulted in much high mineral content. Could the reduction in some minerals have impacted yeast health in a way I had not seen before with higher levels of trace minerals? Also had excess volume in kettle resulting in very clean whirlpool and transfer, virtually zero trub in fermenter which I do know can be helpful as a nutrient for fermentation. I normally aerate first then pitch yeast. I got ahead of myself and pitched yeast first then aerated - Anyone see a problem here?
How to fix this?
I am not inclined to raise temperature as 64 is already towards the high end for 1007 yeast.
I did try to gently rouse the yeast with a very light stir, no noticeable improvement after about 18 hours.
Tempted to toss in a couple pouches of Fermentis K-97 that I have available to see if that will kick it off.
Open to any suggestion to get this beer across the finish line, and potentially find the bug in the process that got me stuck in the first place.
Fermentability - No reason to believe that wort is not fermentable, good mash/sparge.
Good water (RO blend) Ca 93.5 Mg 20.3 Na 11.8 Cl 85.4 SO4 65.4 HCO 55.302 with some additional lactic acid in mash and sparge for pH control. Good mash pH 5.45, step mashed at 145/156/168 with complete conversion based on iodine, good temperature calibration. Started mash with a 1qt/lb infusion, stepped up to 1.6 qt/lb with second add, decoction for mash out. Grain bill roughly 60% pils, 30% munich, 9 % cara, and 1% carafa. Better than expected mash/sparge efficiency, made some adjustments to hit target OG of 1.053.
Yeast Health - Pitched about 350 B cells or .65 B/ml/deg P and aerated wort with a good shake (normal process again, always works)
4L starter made with a fresh pouch of Wyeast 1007 and a bit of nutrient, ran for 2 days until completely finished, and mostly cleared. Starter should have produced ~350B cells for 10 gal batch with starter build, this is about .65 B/ml/deg P. A bit under the .75 that many use, but this is max I can get with a one step starter and have good history with this pitch level for ales under 1.060. Might step this up to min .75 next time as a precaution. Decanted (clear spent wort, good yeast cake in bottom of starter) and pitched at 68 deg then dropped to 64 for fermentation. Wort was well aerated by a good shake in the fermenter.
Equipment/Process Changes - Only recent change to process/equipment is the new use of large RO dilutions for alkalinity reduction, used to use lime treated water which resulted in much high mineral content. Could the reduction in some minerals have impacted yeast health in a way I had not seen before with higher levels of trace minerals? Also had excess volume in kettle resulting in very clean whirlpool and transfer, virtually zero trub in fermenter which I do know can be helpful as a nutrient for fermentation. I normally aerate first then pitch yeast. I got ahead of myself and pitched yeast first then aerated - Anyone see a problem here?
How to fix this?
I am not inclined to raise temperature as 64 is already towards the high end for 1007 yeast.
I did try to gently rouse the yeast with a very light stir, no noticeable improvement after about 18 hours.
Tempted to toss in a couple pouches of Fermentis K-97 that I have available to see if that will kick it off.
Open to any suggestion to get this beer across the finish line, and potentially find the bug in the process that got me stuck in the first place.