That is a nice tutorial but I do not think it actually is making one in the bush. I have only tried burning one out of the end of a log. After the coals burn the inside down to the depth I want I throw out the coals and use a knife to scrape out the charred inside. Slow, tedious and crude, but it works.... however for the amount of time it takes, I could walk out of the woods, break into a house, "borrow" a coffee mug and be set.