I have a bit of an issue with some large nut coke...I've used small nut before and it's worked great!  Burns hot and everything, but now I'm almost out, but large nut (averaging 3 to 5cm) isn't getting hot enough, I made a roaring fire with wood today, slowly placed the coke in the fire, the coke heated up, and got REALLY hot... But only on the sides..The centre wasn't even burning even after alot of poking and prodding and shaping so I started to get quite frustrated...I was wondering if I could request help with this problem. I have a small...I dunno what you'd call it..I guess a small old 'rivet' forge, it's got a hand cranked blower and reasonable room for coke, so by rights it should work, but it doesn't. :(

I've had to use large coke, took a lot of airflow.  Roughly double the airflow that coal requires.

Break it up first, walnut is a bit large for my taste but okay as a max, acorn to peanut seems to work best.

 

Frosty The Lucky.