1.
First you need to start prepping your birds. I do this by cleaning out the cavity of the chicken and then washing the whole bird in cold water. I then dry it off by patting it with paper towels.
2.
Next you want to either grab 2 empty cans, or grab 2 and pour out/drink it (if the are Coca Cola(R) cans, just deal with half of it and you are ready for the next step). Some people do it different ways, but I prefer to cut the top of the can off (inside the lip). I usually just do this with some kitchen shears as they work perfectly for it.
Once you've done that go ahead and fill both cans just about halfway with the Coca Cola.
3.
Now go ahead and insert the cans into the beer can chicken racks that you should have. Once that's done do the same with the chickens.
4.
Now you want to go ahead and liberally coat the outside of the chickens with salt and pepper.
5.
From here you want to insert the rosemary whole into the inside of the chicken so that it rests inside the cans that the chicken is sitting on.
Once you've done that go ahead and clean off your potato and insert it into the top of the chicken, this helps to trap the moisture and make the chicken more moist.
6.
Now you want to pour about 1.5 cups of Coca Cola(R) into a medium saucepan that is on the stove on medium heat.
7.
Add the 1/2 cup of brown sugar to the saucepan and stir until all of the brown sugar has dissolved. Let this reduce for approximately 10 minutes, then remove it from the stove and let it sit.
8.
From here you can go ahead and take the chickens to the grill. Make sure that you are using indirect cooking to do this, otherwise the chickens will burn. If that does happen then make sure you cover the chickens with aluminum foil to prevent further burning.
9.
After about 30 minutes of cooking on the grill, take the saucepan that you combined the Coca Cola(R) and brown sugar in out to the grill along with a basting brush, and baste the chicken every 10 to 15 minutes. This will help to ensure a great tasting and good textured skin on the outside as well as imparting some additional flavor to the chicken.
10.
After the first hour make sure that you are checking the the temperature of the chicken every time you baste it. It takes normally around an hour and a half, but it does fluctuate depending on temperature. You will know when your chicken is done when it reaches an internal temperature of 180 degrees Fahrenheit (approx. 80 degrees Celsius).
11.
Once the chickens have reached approximately 170 degrees Fahrenheit (approx. 76 degrees Celsius) remove your chickens from the grill and let them rest for 5-10 minutes. Due to the carryover in heat they will reach the appropriate temperature and the resting will help to ensure that the chickens stay moist and don't have their juices escaping when cut.