Did my step mash create superwort? 92% attenuation, FG 1.005?

[luckybeagle]

I did my first step mash on this Belgian Dubbel recipe, following the exact temperature schedule:

http://www.candisyrup.com/uploads/6/0/3/5/6035776/maredsous_8_clone_-_040.pdf

The only changes I made are that I used 300 grams of homemade inverted amber/dark candi sugar + 1.5lbs table sugar, rather than the 2lbs of simplicity the recipe called for.

I pitched the proper amount of slurry, and fermented according to the recipe's temperature schedule, but I did NOT rack it off of the yeast on day 5 as I was out of town (and also didn't want to risk oxidation).

I just took a gravity reading on day 10 and came up with 1.005. Taste is nice, dry, not sweet but gives the impression of sweetness on the front end. I carbed up a cup of it via carb cap and the carbonation further depletes the sweetness, which is my goal. I occasionally beat FG estimates, but not for a beer with such a low FG estimate to begin with.

My OG was 1.071. Even with the slightly higher starting gravity, I'm finishing a full 6 points lower than the recipe states... if it's even finished.

Why/how did I reach such a low gravity in 10 days? Is this the sign of an infection or something else? Can I thank my step mash for making a super fermentable wort, or is something else up here?

 

[Ralphie0523]

The yeast in the recipe has a diastatic characteristic to it according to the website for Wyeast. This could be breaking down starches but it isn’t always something that happens.

The step mash could have been a piece but the schedule does not from my view promote a super fermentable wort. A few questions:

1. Did you up to 80 on a ramp prior to you leaving?

2. How vigorous was fermentation prior to the ramp?

3. Did you notice any activity after the ramp when you could monitor it?

4. What was the source of the slurry, a stepped up starter or harvested from previous use?

Basically the theory would be a diastatic yeast that was ramped early would potentially have created conditions that would favor the continuation of the fermentation reaction by breaking non-fermentable starches into fermentable sugars. This could be more pronounced as harvesting methods tend to favor those yeast that attenuate the furthest depending on your method. Open to thoughts and feedback.

 

[bracconiere]

20 mins at 146f would explain it...

 

[dmtaylor]

Caused by highly attenuative yeast, low mash temp, but most of all, >2 lbs simple sugars. The combination of all these factors.

 

[luckybeagle]

Thanks everyone! To answer Ralphie's questions:

1. Did you up to 80 on a ramp prior to you leaving?
I ramped it to about 77F and then shut off my ceramic heatbulb element when I realized the lid of my chest freezer was melting (I will switch to a light bulb wrapped in foil. This was my first time adding heat to a fermentation chamber). I left it alone after this and returned to a 67F chest freezer without the supplemental heat as it's in my attic and the weather has recently gotten cold.

2. How vigorous was fermentation prior to the ramp?
I used a blow off tube, but the krausen layer never got abnormally big (not like a hefeweizen or the belgians I've done with 3522). The other end of the blow off tube bubbled pretty well in sanitizer. I've seen more and less aggressive fermentations. I did not check gravity until day 5, though (at that time it was 1.013, so I assumed it was about done).

3. Did you notice any activity after the ramp when you could monitor it?
No real changes/uptick in activity. It seemed to steadily churn and bubble until about day 5. Day 6, just before we left, I switched to an airlock and saw a little activity (like a bubble or two every 10 seconds).

4. What was the source of the slurry, a stepped up starter or harvested from previous use?
Slurry was harvested from an Affligem Blonde clone (OG 1.064, FG 1.013) and was not washed, just decanted from the mason jar I stored it in. Slurry was about 45 days old. I underpitched according to Jamil's calculator since his viability assumptions drop off dramatically after a few weeks, which brewersfriend disagrees with in their calculator. I pitched an appropriate amount according to brewersfriend, ~500ml.

Does that change or confirm any of the suggestions?

 

[Ralphie0523]

Thanks everyone! To answer Ralphie's questions:

1. Did you up to 80 on a ramp prior to you leaving?
I ramped it to about 77F and then shut off my ceramic heatbulb element when I realized the lid of my chest freezer was melting (I will switch to a light bulb wrapped in foil. This was my first time adding heat to a fermentation chamber). I left it alone after this and returned to a 67F chest freezer without the supplemental heat as it's in my attic and the weather has recently gotten cold.

2. How vigorous was fermentation prior to the ramp?
I used a blow off tube, but the krausen layer never got abnormally big (not like a hefeweizen or the belgians I've done with 3522). The other end of the blow off tube bubbled pretty well in sanitizer. I've seen more and less aggressive fermentations. I did not check gravity until day 5, though (at that time it was 1.013, so I assumed it was about done).

3. Did you notice any activity after the ramp when you could monitor it?
No real changes/uptick in activity. It seemed to steadily churn and bubble until about day 5. Day 6, just before we left, I switched to an airlock and saw a little activity (like a bubble or two every 10 seconds).

4. What was the source of the slurry, a stepped up starter or harvested from previous use?
Slurry was harvested from an Affligem Blonde clone (OG 1.064, FG 1.013) and was not washed, just decanted from the mason jar I stored it in. Slurry was about 45 days old. I underpitched according to Jamil's calculator since his viability assumptions drop off dramatically after a few weeks, which brewersfriend disagrees with in their calculator. I pitched an appropriate amount according to brewersfriend, ~500ml.

Does that change or confirm any of the suggestions?

Thanks for the reply. Nothing else to add that dmtaylor didn’t already cover. Probably a combination of a lot of factors.

 

[luckybeagle]

Hmm... I just checked my gravity with my old trusty glass hydrometer and am seeing 1.009. My refractometer is showing 1.005. I calibrated the refractometer with distilled water, and have it show 0.00 with it, but I'm wondering if it's faulty above that. I opened and closed the clear plastic cover a few times with the beer on the glass and the numbers changed a half a point (from 7.6 brix to 7.0 brix). Maybe I should just go back to the old glass one and stop fiddling with this thing?

 

[dmtaylor]

I opened and closed the clear plastic cover a few times with the beer on the glass and the numbers changed a half a point (from 7.6 brix to 7.0 brix). Maybe I should just go back to the old glass one and stop fiddling with this thing?

The initial reading of 7.6 is most likely the correct one. The more you click and clack around with the plastic cover, the more likely there will be some effect due to evaporation or temperature or who knows what else. Calibrate again, measure again, and see if you get 7.6 again. Then you'll have your answer... and you should find that it equates to about 1.008-1.009 or thereabouts, consistent with your trusty old hydrometer.

 

[luckybeagle]

The initial reading of 7.6 is most likely the correct one. The more you click and clack around with the plastic cover, the more likely there will be some effect due to evaporation or temperature or who knows what else. Calibrate again, measure again, and see if you get 7.6 again. Then you'll have your answer... and you should find that it equates to about 1.008-1.009 or thereabouts, consistent with your trusty old hydrometer.

Thanks dude. Maybe the website I'm using for calibrations is inaccurate? https://brucrafter.com/convert-brix-to-sg/

I got a 1.071 for OG (17.22 brix). When I plug my OG and FG 7.6 brix) in on that site, I get 1.005 FG. Maybe 4 points is within the margin of error and I shouldn't worry about it? Maybe I should buy a digital refractometer

 

[dmtaylor]

Thanks dude. Maybe the website I'm using for calibrations is inaccurate? https://brucrafter.com/convert-brix-to-sg/

I got a 1.071 for OG (17.22 brix). When I plug my OG and FG 7.6 brix) in on that site, I get 1.005 FG. Maybe 4 points is within the margin of error and I shouldn't worry about it? Maybe I should buy a digital refractometer

Oh my, that calculator is way off. Use this one instead:

https://www.brewersfriend.com/refractometer-calculator/