One main key to cooking perfectly grilled foods is maintaining the proper temperature. You do this by controlling the flames by knowing when to have your charcoal grill vents open or closed.
More than just an exhaust for smoke, your charcoal grill vents (aka grill damper) serve a very important function in cooking.
Learn how these vents affect your cooking.
Charcoal grill vents regulate the flow of air into and out of the grill. This airflow is what feeds your charcoal with oxygen.
There are two vents in charcoal grills—bottom grill vents and top grill vents.
The bottom grill vent is called the intake damper, which lets air flow into the grill. This is what actually provides the oxygen needed by the charcoal so it can produce intense heat.
The top grill vent is called the exhaust damper, which releases smoke and excess heat from the grill. This serves as the passage for air outflow.
Together, these vents control the cooking temperature by regulating the inflow and outflow of air in the grill. One cannot function properly without the other.
The vents control grill temperature by simply controlling the amount of oxygen that feeds the flames. The top and bottom grill vents work hand-in-hand to produce the desired quality of flames for cooking.
The cooperation of the top and bottom grill vents works like this:
If the top grill vent is covered, smoke and gases build up and cause the pressure inside the grill to increase. With increased pressure, air from the environment cannot flow into the intake damper. And without fresh air bringing fresh oxygen, the fire dies out.
Thus, it is important that both the top and bottom dampers are opened just right so the charcoal produces just the right amount of heat.
The grill temperature is determined by the following principles:
To control the flames and set the right temperature, the solution is to not cover up the top or bottom grill vents but to adjust the amount of passage or opening.
Depending on the type and brand of charcoal grill, the grill vents can be adjusted through different settings. For example, on a Weber Kettle, the bottom grill vent’s opening can be adjusted from fully closed to fully open by swiveling the vent lever along the gauge.
Usually, if you want to make the flames smaller, you would set the bottom grill vent between a quarter and half open. This decreases the amount of air flowing into the grill compared to when it’s fully open.
If you want to make the flames bigger without letting them ravage your food, set the bottom grill vent at half open or between half and fully open. The airflow creates stronger flames but not as strong and big as a fully open vent produces.
Aside from vent settings, the quality of the grill flames can be influenced by other factors:
Physical location and weather conditions can directly affect how your grill produces flames.
In a windy environment, the flames produced tend to be stronger because more air flows through the vents.
On the other hand, in a dry environment with few air drafts, the flames produced might be smaller and weaker no matter how you adjust the vents. In this case, using a fan to encourage air draft is helpful.
Grills that have leaks are difficult to regulate the flame quality. This is because the leaks act as false vents.
Leaks at the bottom can introduce more air into the grill despite frequent adjustments to the bottom vent’s opening. This will make your flames stronger than you may want.
Leaks around the lid can let out more air in addition to what the top grill vent already pulls out. This will make your flames smaller and weaker even if you adjust the bottom vent to fully open.
If you have a leaky grill, you should patch the leaks with a food-grade sealant or buy a better grill (if you have the money to spend).
Learning how to use your grill’s vents can help you achieve grilling perfection. Though some environmental conditions can make your flames run amok, flames are tamable and you can manage them with the simple science of airflow control.
By mastering the use of your charcoal grill vents, you can avoid wasting food, time, and money from rogue flames. This can take some trial and error to learn your grill though - so don't give up.