I brewed an 1.075 o.g. IIPA a couple months ago that went through a 3.5 week primary fermentation then a 3 week dryhop in secondary. I ended up with a final gravity of 1.029, only 8 points higher than what the recipe called for. After 2 weeks of conditioning, the beer is far too sweet for an IPA.
My only wish is that I had let the beer ferment out a bit longer in primary.
Now my question is: would it be at all crazy to uncap the beer, pour back into a fermenter and repitch yeast in order to bring that gravity down?
Yep, that's crazy talk!
First, it's probably done for some reason at 1.029. The only thing you'd gain from pouring it into a fermenter at this point is oxidation, unfortunately. If you don't have bottle bombs by bottling at 1.029, that means the yeast is done but I have no idea why.
It could be sweet because the beer is underhopped, underattenuated, the priming sugar is unfermented, or a combination of all three.
If it's too sweet, so that it's undrinkable, maybe a pinch of yeast added to each bottle might work. But that's unlikely to fix it, as you've got a 6% beer that may or may not be finished.
What I'd probably do is take out a bottle, open it and add a tiny pinch of yeast and recap. Leave it out where you can see it and monitor it, but cover it in a cabinet to protect it from light and shrapnel just in case it DOES start up again. If it starts up again, and finishes at a decent Fg, then you sort of know how to treat the rest of the batch.
That isn't any sort of "expert advice" at all- that's just what I'd probably do!