Sudden cessation of fermentation

[Adrian Gresores]

Something very strange happened today. Four days ago, I started fermenting an IPA. I'm using Imperial Yeast A24 Dry Hop at 68 degrees F. Expected OG was 1.067, but I only got 1.060. No big deal. Started bubbling within 12 hours. Went out of town for last 2 days. When I came back today, the blow-off tube was bubbling every 4 - 5 seconds and gravity had dropped to 1.020. I then decided to switch the blow-off tube to a 3 piece airlock, since the krausen was not that thick. However, from that moment, about 8 hours ago, there has been no bubbling in my airlock! In addition, the gravity has not dropped at all (I have a Tilt hydrometer, so I know the gravity continuously).

Anybody have any idea why this might have happened?

Thanks,
Adrian

 

[oliver]

test it next to a triple scale hydrometer? See if you get the same results..

If you do get the same results, bump the temperature up into the 70s, give the fermenter a little rousing, see if that wakes it up.

 

[The Brew Mentor]

I'm sure everything is fine.
Unless it's a very high flocculating Yeast, it's just slowing down as it nears the end.
I'd walk away for a few days, or a week really, and then take a look at it.
Raising it up to 70° will also help it to finish.
Good luck and fill us in a week from now.
Brian