One thing about the bag trick is, it allows fungus and bacteria to attack the wood, since the surface is kept moist.
That is what makes some of the whiter woods, maple, holly etc. grey and mottled.
Woodturners face the same problem, when drying rough turned bowls: if you dry them too fast they split, too slow and they get discolored.
Years ago I started working on a solution. First I tried dipping them in a solution of potassium sorbate, a food preservative. That worked ok, but a simpler solution turned out to be dipping them in a solution of citric acid.
That makes the surface ph so low, that fungus cannot grow on it.
When I re-turn the bowl, I cut the treated part away. In the case of a spoon, just wash it before drying it out before applying the oil finish.
I was goint to write an article for American Woodturner about this and did some maple bowls, both treated and untreated for pictures. Then we had a fire and I lost the bowls, so the article never got written.
Stephen, just boil the burl for a couple of hours, that should keep it from splitting.