When you need to cook more slowly and gently on the grill, a water pan may just be the ticket.
Some grill experts put an empty aluminum pan in the grill in order to catch drips and prevent flare-ups. For recipes such as our Sweet and Tangy Barbecued Chicken (see related content), we not only put a pan on the grill but also fill it with water—for different reasons: Placing a pan of water opposite the coals lowers the heat inside a grill, allowing you to cook more slowly and gently; it also evens out the heat. But we weren’t sure which component—the water or the pan—was more responsible for these benefits.
EXPERIMENT: We gauged the heat disparities on three different grill setups by running a toast test. We built indirect fires in each grill and then placed a disposable aluminum pan opposite the coals in one, an aluminum pan filled with 3 cups of water in another, and nothing in the third grill. We let the coals burn for 15 minutes and then spread six slices of bread over each grill’s cooler side and let them cook for 4 minutes.
RESULTS: Bread toasted on the grill without a pan turned dark brown and the pieces closest to the coals burned, while the slices cooked on the two grills with aluminum pans were lightly and evenly tanned. The bread toasted over the water-filled pan was slightly paler but not by much. The grill temperatures correlated with the toast results: The grill without the pan registered 415 to 425 degrees, the grill with the empty pan 385 to 395 degrees, and the grill with the water-filled pan 375 to 385 degrees.
EXPLANATION: Even putting an empty aluminum pan in the grill will significantly drop its temperature. Aluminum is very efficient at absorbing heat, allowing it to lower the temperature inside the grill by about 30 degrees and to even out hot spots. Water added to the pan captures more heat, helping drop the temperature even further, but it’s mainly the metal pan that’s responsible for the change. So if you ever put an empty pan in the grill to catch drips, be aware that it will lower the temperature as well.