Ah, that makes a lot of sense. In his setup, digging a trench and placing a clay tube into it to get the air to blow upwards into would be better then. He has another video of where he makes lime from snail shells. I wondered why he wasn't adding some of that into the process. Today I also learned that lime.org is a thing. https://www.lime.org/lime-basics/uses-of-lime/metallurgical-uses-of-lime/iron-and-steel/