Wyeast 3068 fermenting happily at 15C (59F), leave it?

[Elkoe]

I switched to using a 3.5mm female jack plug in the lid of my fermentation bucket, for an airtight easy to connect sensor setup. Turns out these can't be trusted. Due to a flimsy connection, my sensor stopped working and the fridge cooled my beer from 18 to 14.5 degrees while I was asleep.

But now the good news: fermentation was still going strong! At 15 degrees, 3 degrees under the recommended range of 18-21.

I have fixed the sensor and the beer is still at 15 now, with bubbles in my blow-off bottle every second.

I am hopping the **** out of this beer, so I want to keep the banana flavors down, but 15 is a bit crazy.

Or is it? What do you think? Leave it at 15? I have heard of 3068 producing sulfur at low temperatures, but nothing so far.

 

[bull8042]

Personally, I would let it warm to the low end of the scale (18°C) and call it good. I doubt seriously that 3 degrees is going to make much of a difference, plus your temp probe could easily be off a degree or two as well.
Obviously, fermentation did not stop, so I can't imagine you will suffer any issues due to this.