SUMMARY: I have always used my Large for overnights and have been amazed at how long it goes. I did a pork butt recently for 20 hours and there was still a LOT of leftover lump. However, I used my Medium Friday night and it appeared to run out of lump at about 16 hours. Is that about as long as one should expect with the Medium?
FOR THOSE THATA WANT ALL THE DETAILS, here is the chronology. I completely cleaned the ash out and stacked the lump carefully (for most cooks I just pour in the lump). I lit it about 6:30 p.m. and had the fire stable and the meat on by 7:00 p.m. I had calibrated my dome thermometer, so I know it was accurate. Most of the evening I kept it at about 230 dome. It crept up to about 250 in the night which was fine. I had to go to a funeral and left it about 10:45a.m. Since I felt like the meat was getting ahead of schedule I dialed the vents down pretty low. When I got back at 12:15 p.m. the dome was down to 190 and I could not get it back up. Obviously, the fire had gone out. I figured I had been too miserly with the vents. However, when I opened to relight there was almost no lump left at all. Now, it is possible that had I not been so miserly with the vents it would have still been going.
It all worked out fine as I quickly got the fire going with more lump and the timing still worked out great and the meat was superb. I am just curious if I should always use my Large when doing long cooks when it is available. This time I had a 15lb brisket going in the Large, so I had no choice.
League City, TX