Just a thought here, the air flow isn't much when you're up to temp. and I'm sure all our drums are pretty similar. I wonder if the length of pipe you have attached to the barrel bung is cool enough at the upper end for any moisture coming out of your food to condense on the inside of the pipe and run back down into the smoker. I'm not sure what the reason for the long pipe is, and do you have a damper on the top? All my cooking in my barrel is with the top vent wide open. The air flow is regulated by the bottom vents. Try doing a cook with the pipe removed to see if that corrects the problem. I can't think of what else it might be.