« on: March 13, 2017, 10:04:28 AM »
If you'd like some assurance that it's absolutely done, you could pull a sample and pitch a packet of dry yeast in it. Keep the sample warm and shake it once in a while. If the gravity of the sample doesn't change after a few days then you can be absolutely sure that it has finished. If the gravity does drop, then you'll probably need a large volume of fresh yeast for the rest of the batch (like some slurry from a local brewery or the yeast cake from another batch).