Trying to make Charcoal

My brother is off his usual work this week and instead splitting some firewood to sell. As he's up the field all day we thought it would be good to try and make some charcoal.

We modified a 45 gallon oil drum so it had air holes in the bottom and made sure that the lid would fit. We then started a fire in the bottom and quickly stacked the wood inside letting the fire build up. Once it was going well we sealed the top and the air holes at the bottom using soil and let the drum cool down.

For our first attempt we made a little tiny bit of charcoal and some warm logs. Reading a few sites on the internet we need to leave the bottom holes open longer and let the fire build up more in the first place. I'm going to get to the farm early tomorrow so we can try again.