A charcoal fire burns hotter with more air. The bottom vent lets air in and is your main control: open it to raise the heat, close it down to lower it. The top vent lets smoke out; keep it at least half open, set over the food. Make small changes and wait 10 to 15 minutes for the grill to settle.
How air moves through the grill
- Bottom vent: air in, feeds the fire
- Coals: more air, hotter fire
- Food on the cool side
- Lid vent: smoke and heat out
Think of it as a chimney. Air pulled in at the bottom feeds the coals; hot air and smoke rise and leave at the top. The more air passes through, the hotter the fire burns. Closing the top vent too far traps stale smoke, which makes food taste bitter, so steer with the bottom vent first.
Starting vent settings
For a kettle grill with a typical load of charcoal. Every grill and every day is a little different, so treat these as starting points and adjust.
Low and slow smoking225 to 275 F
Roasting and chicken325 to 375 F
Searing450 F and up
Putting the fire outAfter the cook
The bottom vent does the work
Every change at the bottom vent changes how much air reaches the coals. Move it in small steps, a quarter at a time, and wait before moving it again: a charcoal fire responds slowly, and chasing it with big swings makes it overshoot.
Keep the bottom clear of ash. A pile of ash under the vents blocks the air and lets the fire fade, so empty the ash catcher before every cook.
When the fire runs too hot or too cold
- Too hot: close the bottom vent by a quarter and wait 15 minutes. Do not open the lid to cool it; fresh air feeds the fire and it climbs further.
- Too cold: open the bottom vent, check the ash is not choking it, and give it 15 minutes. If the coals are spent, add a few lit ones from a chimney.
- Swinging up and down: you are adjusting too much, too often. Make one small change and leave it.
- Wind: it blows extra air through the vents. Turn the bottom vents away from it, or close them a little more than usual.
Kamados work the same way with tighter control, because their seal and thick walls let so little air in elsewhere. Our kamado guide has its own vent settings.
Charcoal grills that hold heat well
Questions people ask
- Should the top vent be open or closed?
- Open, at least halfway, for nearly every cook. Close it fully only to put the fire out, together with the bottom vent.
- Where should the lid vent be?
- Over the food, on the opposite side from the coals, so heat and smoke are drawn across the food on their way out.
- How do I keep a charcoal grill at 225 F?
- Light only a little charcoal and let it catch a larger unlit pile slowly, set the bottom vent about a quarter open and the top about half, and adjust in small steps. Our charcoal lighting guide shows how much to light.
- How do I put out a charcoal grill?
- Close the lid and both vents. Without air the fire smothers within an hour or so, and you can reuse the unburned coals next time.