There's no real good answer to this from the perspective of someone new to all this.
What El Ropo said is true, but not in all cases because making clean thin blue or even clear smoke when using wood in your fire is mostly only possible with offsets or cookers that likewise have a small, clean burning fire.
For all other smokers, or anyone using the Minion method, then you're not making such a fire. Instead you are making bed of charcoal burning in a controlled directional manner with a few wood chunks mixed in along the way. In those cases, those chunks aren't necessarily burning in a clean hot fire, and may produce a bit of white smoke as they light up. What saves them is that the surrounding coals should ignite a fair portion of those volatile compounds being released, and the ones that remain simply won't be in high enough levels to negatively affect your food, yet still impart a smokey flavor to the food.
So, in that regard, you could oversmoke your wood by having too high of a ratio of wood chunks to charcoal with a Minion burn that has too few lit coals to burn off the crap released from all that wood.
When you boil down, in essence, what I just said though..even that is saying it wasn't a clean fire. But that does not mean you have to use an offset and make a small, hot, clean burning fire. You can use a vertical smoker and the Minion method and make great BBQ. You just have to make sure you are allowing for however much wood you are burning to burn as clean as possible.
It sounds more complicated than it is, really. You'll get it.
Last edited by bigabyte; 03-20-2013 at 10:01 PM..