2 carboys, 1 yeast.... 2 different gravities?

[nuckboozy]

I pitched 3787 slurry into a “light” 1.070 OG Belgian Style Tripel. I split the slurry between the 2 carboys evenly and put them into my fermentation chamber at 64F. I’ve ramped temp up to 71 over a 7 day period. I can’t seem to go higher unless I put in a more powerful foil wrapped bulb as the chest freezer is in a cold garage, but I am able to hold 71F.

Carboy 1 is beginning to drop clear and is showing 1.011 FG.

Carboy 2 is stuck at 1.020.

Same beer, same slurry, same ratios...what gives? I roused the 1.020 carboy but am still not seeing movement 24 hours later. Thoughts?

 

[Gnomebrewer]

When you filled the carboys, did you fill one then the other? Your wort might have stratified, meaning one carboy might have had more of the sugars than the other.
The slurry for one might have been more yeast rich than the other. Was the slurry well stirred?
One might have been closer to the heat source than the other.
One might have been more oxygenated than the other.

 

[luckybeagle]

Hi gnome, I'm the OP but posted from my mobile under an account I never intended to use

I filled one, then the other--however, I whirlpooled my kettle before chilling. It sat "hot" for only about 10 minutes before running it through my plate chiller.

I shook up my decanted slurry aggressively before pitching. Both carboys got the put-it-on-your-knee-and-shake-the-devil-out-of-it treatment. I usually brew 10-11 gallon batches and haven't had this happen before.

The underattenuated carboy was next to the heat source and may have actually gotten a few degrees warmer (probe was connected to the fermented furthest from the heat source)

Not a great picture, but the carboy with the orange handle is the underattenuated one. The heat source is a lamp with a bulb wrapped in foil in the upper right of the photo (you can see the base of it sitting on the chest freezer's compressor box). To the best of my knowledge, since the garage the chest freezer is in is ~50F, the chest freezer has not had its cooling come on at all.

I'm perplexed!