Nancy Reading wrote:
Final yield was slightly disappointing, the volume has reduced quite a bit and there is a bit of ash indicating that the twigs were burning a bit in there. Either the fire was too hot, or oxygen was getting into the tin. I can try letting the fire die down a bit first when I try it again.
Mark Brunnr wrote:Hi Nancy, I think the issue was the holes/seal of the container letting in oxygen, which let your coals burn down to ash. While you don't want a tight seal causing gas pressure buildup, there shouldn't be any visible gaps/holes in the container. That round hole in the top of the lid was sealed correct? I'd say the gaps around the edge would also need to be smoothed out.
Ellendra Nauriel wrote:My in-stove charring containers all have a hole punched in the top to let gasses escape. I've never had any of them go "bang", even when the fire smoldered. The way my containers are, the lids are only held on by gravity, so if the vent hole gets plugged the pressure still has a safe way to escape. Maybe something like that would help?