I had always observed mostly white smoke coming out of my masonry offset smoker, because I would add wood while smoking. Yesterday I smoked a pork loin that I figured would take about four hours. Knowing that if I load the firebox well, that I could keep a fire going for a good eight+ hours without adding wood, that's what I did. I fired the smoker up early in the morning and after getting a good base of glowing red wood coals as a base I filled the firebox maybe 3/4 full with wood (oak). I let that burn for about three hours until the white smoke diminished and little smoke was coming out of the chimney - and what did come out was thin and blue-tinged. Then I smoked the pork loin for about five hours until it got up to 160. Everyone in the family said it was the best pork they had ever had. I'm not sure it was THE best, but it sure was dern-tootin' good! Okay, so I can do this when smoking something for maybe six hours or less. But what about when I smoke a pork butt or anything that you want to smoke for 12 or more hours? You have to add new wood. Are some experts able to add wood during the smoking process and avoid it making lots of white smoke? If so, how? Thanks!