First, don't soak your smoke wood...it just delays the onset of smoke. I'm not familiar with your smoker, but when you say the chips are burned up after 15 minutes, do you mean charred black or burned to ashes? If they are ashes in that short of time, there is way too much heat and air getting to the smoke wood, and you need to regulate that somehow. Also, chunks will burn slower than chips due to having less surface area, so a switch to chunks would be another step to take. If there is no easy way to reduce the heat to the smoke wood by elevating the pan/box higher above the heat source, then put the smoke wood into a metal container which can be partially covered, such as a tin can with lid. This will limit the amount of air getting to the smoke wood.
The smoke will normally come on heavy and white...this is due to flashing off of water vapor and a small amount of volatiles from the wood, then should turn to a thin blue smoke withing 10-20 minutes, depending on the amount of wood, heat and air getting to the wood. A slow smoke with just a couple of hands full of chips can last for 4-6 hours in some smokers, if regulated to do so.
Smaller cuts of meat need smoke for less time, larger cuts for more time, depending on your personal tastes.
Eric
