Now wedge the piece of onion into the neck of the chicken to seal the top of the bird. This holds the moisture inside and is the real secret of beer can chicken.
Close the lid on the grill and wash everything. This is my rule with chicken; when the bird is on the grill everything that did or could have touched that bird has to be washed. When the chicken is done and ready to come out, there shouldn't be a single germ left behind.
Try to maintain a grill temperature around 300 to 325 degrees F. (150 to 165 degrees C.) during the cooking time. Of course, you can smoke this bird, but it should be cooked at a temperature several degrees above the boiling point of water. If not, then the liquid in the can won't do anything for the bird. If you decide to smoke your beer can chicken, choose a temperature around 250 degrees F. (120 degrees C.)