See the nice blaze that the split bamboo poles make. They have to be split though because any trapped air inside the sealed nodes can cause an explosion when heated.
When we've gotten tired of tending the fire, we let it get to the stage where it's mostly just hot coals. This one was a little past that stage - it was getting relatively ashy on the outside.
So at this point quenching with buckets of water, will stop the burning and leave you with mostly charcoal instead of ashes.
Beautiful and soggy "black gold".
This is a big plastic pot full of [well-cooled] charcoal. It looks whitish because there's a layer of ice coating the surface. We're letting this batch weather a while before we use it. I have it sitting next to some comfrey plants so that any ashes leaching out will go to good use (fertilizing the comfrey).
An example of its usefulness: I've used it dug into the planting holes when planting hardy kiwi vines to prevent root rot. The kiwis have thrived. All three times I've tried growing kiwi before (without charcoal) they've always died.
I've also seen charcoal powder cure container grown iris seedlings of some sort of root rot.
We're experimenting with using it in the vegetable garden. It's supposed to increase the cation exchange capacity of the soil (a measure of the soils ability to hold onto elements like potassium, calcium, magnesium etc. I haven't personally seen anything convincing from what we've used so far for soil improvement, but it's only been a short while for that. On the other hand, those cases of rescue from root rots have been pretty convincing to me.