Re: coconaras coals red but not ready?
I wouldn't worry about it. I've noticed this on every coal I've ever used and never had a problem. I never bother flipping my coals. Maybe I should.
But, oxygen is necessary for something to burn, I'd assume that includes coals. The bottom side of the coals are getting very little oxygen compared to the rest of the coal. It's bound to get dark.
This is my: