I have came across a few pieces that were checked and cracked pretty good, but still sizzled and hissed when put in the furnace. Yet I have come across some that were NOT checked and cracked, that burned without sizzling, steaming, foaming, etc. whats the deal? Also, what effect does extreme cold have on it? I have some stuff in my woodshed (fully enclosed) that when put in there in october was nice and checked/cracked, but now doesnt seem to be as much? but if I take some down near the furnace, its cracked again!