Originally Posted by dpittard
Do you have a hydrometer?
There's no set time to leave a beer in the fermentation chamber. Take a hydro reading to determine if fermentation is done. Sample the beer after the reading. If it tastes "off", then give it another week or two and do the same thing.
+1, the only way to confirm that fermentation is completed is by taking gravity readings. Needs to be a flat line for 2-3 days.
If FG is much higher than expected, you may have a stuck fermentation, but that is another thread.