So, I know there is the debate between stacking and dumping. I'm I'm between - I dump for short cooks, but stack for long cooks. I usually pull out big pieces and save them to help with the stacking. When I went to do a pork butt yesterday, I had so many big pieces that I just stacked em all up and didn't put many medium or small on top at all, thinking lump is lump. About 11 hours in my temp started to drop, but didn't matter too much because the butt was 193 so I just pulled it. Examination of the fire box showed that the big pieces created so much ash it was killing the air flow. Going forward, I think I'll cut down on the number of big pieces I use. Hope somebody can learn from this experience.