Hi NFD, thats a great question and something I get asked a lot.
The primary methods for controlling temperature are:
#1: The amount of lit charcoal you have
#2: The amount of oxygen available
#3: A combination of 1 and 2
Since you asked about indirect, lets assume that you are banking your coals along one side for all scenarios described. (
example of banked coals, firebricks are optional. I personally prefer to use a
weber charcoal basket)
For LOW heat (200 - 250, which is the typical bbq range)
Start with 2/3 of a chimney of unlit coals, bank them along one side of your kettle.
Fire up 8ish briquettes in your chimney. When they're ashed over, add them to your bank of unlit.
Keep the lower vents mostly closed and the top vents about 1/3 close (2/3 open)
This should keep your temps low for several hours. The more you open your lid, the higher temps will go (because you're letting in air)
If you're scared of high temps, start with 8 or 10 lit and add fresh unlit on top when your temps get low. With this method, you can keep your vents wide open.
For MEDIUM heat (275-350)
Same as above, but use a half chimney of lit
For HIGH heat (400-500)
Use a full chimney on a thin bed of unlit. Add unlit on top as needed.
Keep in mind, adding unlit kingsford to an already hot bed of coals will produce a funky white chemical smoke.
Many people don't mind this, but it drives me nuts.
I like to keep a few different brands of charcoal on hand just for this.
I use kingsford in my smoker, but I NEVER add unlit kingsford to it. I'll add lump or coshell instead.