Heat Control

I know we have talked about this before, But Saturday at the Vintage Faire, many of our visitors were new to Dutch oven cookin', and the question was asked, " How do you know how many coals to use?" There are two or three schools of thought on this, But the one that works well for me is, most all things cook at 350°f. to reach that temp, here is the rule of thumb I use. Size of oven. The size number is on the lid 12, 14, 16, and so on. That is 12", 14" 16" Take the number on the lid, i.e. 12 add 2 to that number ( 14 ) and put on top, Subtract 2 from  that number  ( 10 ) put that number of charcoals on the bottom.  A 10" 12 and 8, a 14" 16 and 12 and so on. That is a starting place. If its a cold day add 2, very cold add 3 to both top and bottom .