I'm making biochar today in 2 55 gallon barrels. I put half inch holes about 2 to 3 inches apart in a circle around the bottom in the flat bottom part. I'm not sure this would work as well in dryer climates but here in the Midwest it seems fine. I'm not doing a water quench. I just put the lid on it and let it set overnight.

It seems to work a bit better for me than the saddle cut version, and I don't always have water where I'm working to quench.

When it's cool, I will dump it into a plastic barrel and let it fill up with water.

With a temp gun I'm getting temperatures in the bottom on the outside of the barrel as hot as 1,000° today with Eastern cedar feedstock.

The last batch I made I fed too fast, and it was a bit under done, so today I'm going slower.