Fermentation Despite Cold Crash

[GreenLion]

I was away for this weekend, and I didn't want all my fermenting ciders to ferment too dry, so I put one of my 1 gal jugs into the fridge on Friday. When I returned Sunday afternoon, the cider had continued fermenting despite the ~40 degree temperature, and had dropped 13 gravity points. An identical jug that was not cold-crashed dropped 14 points.

Is 40 degrees an insufficiently low temperature to ensure stopping fermentation? Also, I did not rack the cider off the yeast prior to putting into the fridge - is this always necessary to stop fermentation, regardless of the temperature?

I'm somewhat confused because I used Nottingham yeast, which I thought has a low-end fermentation temp of 54 degrees. Any feedback on what happened here would be appreciated.

 

[Priemus]

Yeah that is low enough that it "should" have put the notty to sleep. I read on the danstar site a while back that it works at 12C degrees, which is around 50F, so I "guess" the answer is that the temp might have been 40 in the fridge, but then its activly fermenting so that in itself raised the temp a few degrees, not to mention it takes a long time to cool down a Gallon to 40 degrees.

Just a lag time, and active notty yeast keeping the temp up a little?

All theory.

 

[SaltyTX]

low end doesn't necessarily mean stop completely.

I had a 5g carboy in a fridge down in the mid 30s and the gravity still changed about 7 pts in 2-3 weeks.