I have a 18.5 WSM and continue to have issues with white smoke. The only time a chunk of dry wood will produce a thin blue smoke is when I do chicken at a high temp, all vents fully open. The problem starts when I smoke something like a pork butt or chuckie at around 230-250. For example- smoking a chuckie at 240deg, bottom vents at 1/2 and top open with blue bag minion method. My fist size chunk of hickory or apple wood will first produce thin blue but will always begin to produce a lighter white colored thick and bad smelling smoke that will cause me to open the door and remove that chunk of wood which is now smoldering and has white colored ash starting a corner. I will then have to get a new chunk of wood and start all over again. I just don't understand the guys here that burry numerous chunks inside the coals, if were to do that, I would have some bad tasting meat in the end. An all day smoke means an ALL day smoke where I have to keep a constant eye on what my wood chunks are producing. I would appreciate any help from you fellow smokers.