This was a big hit this past Christmas. A fairly easy mod to roast a 17lb turkey on my propane BBQ grill...
Step 1: Choosing and Preparing Your Bird
There are a couple of rules that you have to follow to successfully roast your turkey on a propane grill. First and foremost, don't get a bird that is too large for the grill! This is VERY important. When the turkey is on the rack with the lid closed, NO PART of the bird can be touching any part of the lid or sides! Make sure the you choose a turkey that will be at least 1.5 to 3 inches away from the surface of the grill on each side. My grill is a fairly standard model and I had absolutely no problems with a 17lb turkey. I could probably have gone as high as 20 lbs. If you have any doubts about what size turkey to get, just measure the inside of your grill's length, width and height and go to the store using the measurements as your guide. Be sure that you get a turkey that will be at least 1.5 to 3 inches SMALLER than your measurements on ALL sides (Including the TOP). Make sure that the bird is fully cleaned and pat dry.
A good second rule to follow is to not stuff the turkey with bread stuffing. Roasting a bread stuffed bird is possible, but it will add to the cooking time. What I suggest is to stuff it with some onion, apples, pears, and lots of fresh rosemary and sage. Just cut the onion, apples and pears into quarters and stuff them into the bird with the fresh rosemary and sage. Make sure to fully stuff it so that everything is tight inside. This will help the turkey keep its shape while cooking. Then, put a whole apple and/or pear on the end to keep everything in and tight. Here's a shot of my fully stuffed bird.
Once the bird is stuffed, make sure that it is tied so that the ends of the drumsticks are together and that the wings stay close to the breast. Note how I just tucked the drumstick ends into the flap of skin near the opening for the stuffing. I then just used string to keep the wings tight to the side of the bird. Try to make it as tight a ball as you can. Once it's tied, you can either butter the skin or keep it dry. I prefer to keep it dry because it makes the skin crispier.
Step 2: Preparing the Grill
My grill is just a regular propane grill that you find at any Home Depot, Lowes, Walmart or Target. Pretty standard. It's got two burner controls and a side burner (but we don't use that)
Getting the grill ready for roasting your turkey is easy. You'll need the following items:
Heavy Duty Aluminum Foil (The thick stuff is best)
A couple of cheap foil muffin pans (the six muffin kind worked best for me)
One shallow square pan slightly longer and wider than the turkey (for drippings)
A spray bottle filled with water (To knock down any flare-ups)
A pitcher of water.
Optional: Wood chips for smoking and pan to soak the chips.
The first thing you have to do to prep your grill for roasting is to remove the upper rack from the cover. You'll need to have plenty of room on the inside to be able to close the lid without the bird touching anything.
Roasting requires indirect heat. This means that no flame can touch the food being cooked. In order to make sure that the grill will heat indirectly, you have to block the flames that usually burn in the center of the grill and force the heat to come up the sides. You do this by wrapping foil around the bottom plate of your grill. The bottom plate is the metal plate that is directly above the gas burners. At this point, you have a choice. I use smoking wood chips to add flavor to the bird as it cooks. This means that I have to keep a little of the bottom plate unfoiled to allow for the flames to reach my wood chips and get them to start smoking. The pictures below show how I foiled my bottom plate.
I removed the bottom plate and wrapped foil around the center TWICE. This blocked the flames from coming up through the center of the grill. Note how I left a little on each side to allow some flames to hit my wood chips. I used Apple Wood chips, but you can use Mesquite or other flavorful smoking wood.
If you don't want to use wood chips, cover the ENTIRE bottom plate with foil.
Step 3: Wood Chip Holders, Stand-Offs & Drip Pan
Next, I made some wood chip holders for each of the open sides. The chip holders are simply heavy-duty aluminum foil with holes poked through the bottom to allow the flames to hit the wood. I just poked a bunch of holes into the bottom and made sure that I could see the flames right under most of the holes but kept it sturdy enough to hold the wood chips while they smoked. IMPORTANT: Make sure that you soak the chips for at least an hour before placing in the baskets. This lets them smoke without bursting into flames often. I keep a pan of chips soaking on the side and refill it when the chips start running low.
Remember: Make sure that the entire bottom plate is covered by either a foil wrap or covered by your wood chip containers. They key is to block all flames from going straight up. You want to force the heat to the sides
The next step is to set up the muffin pans and the drip pan. I use the foil muffin pans as stand-off spacers for the drip pan. I set the muffin pans directly onto the foil of the bottom plate and then set the shallow drip pan on top of them. The reason I do this is to try and protect the drip pan somewhat from the direct heat of the bottom plate and the muffin pans are flexible enough to squash them a bit to get the drip pan to fit under the grill rack. With the drip pan above the bottom plate somewhat, the liquids in the drip pan won't boil away as fast as they would if the drip pan was sitting right on top of it. Note: Most of the liquid will boil away anyway and, at the end of cooking, you will have mostly turkey fat so it won't be useful for gravy made from drippings.
In the shot of the drip pan resting on the muffin pans, notice how the pan allows for space on all sides.
I put some celery, apples and pears along with some rosemary and sage into the drip pan and fill it about 3/4 full of water. This helps to keep things fairly moist inside while cooking and helps to flavor the bird.
Now, make sure that the drip pan is stable on the muffin pans and place one grill rack over the drip pan. Be sure that the grill rack sits stable and that the drip pan is not touching the bottom of the rack. Notice that I have allowed the drip pan to jut out a little more on the left of the rack. This makes it easier to add water during cooking. You can cook the turkey directly on the grill rack or, as I chose to do, place a roasting pan with drip holes on top of the grill rack. I think that it keeps the bottom a bit more moist and makes it easier to remove the turkey when it is finished.
Step 4: Cooking Your Turkey
Once you have the layers set up, it's time to preheat the grill. Fire up the grill on High heat and let it warm up for about 10-15 minutes. This gives everything a chance to get hot and the wood chips to start smoking. (Don't worry if the chips don't start smoking at 10 minutes. They'll catch up soon enough).
When the grill is pre-heated, place the turkey in the center with foil over the breast area. This keeps the top of the bird from charring during cooking.
Make sure that no part of the turkey touches the sides when you close the lid. Turn the dials to LOW and close the cover. Some grills, like mine, have large openings on the sides where the second shelf assembly sits.
When the lid is closed, use aluminum foil to plug these holes so the smoke stays in and the temperature stays fairly constant. You don't have to worry about the other holes in the lid.
If you're using wood chips, keep your eye on it for the first hour or so to ensure that the chips have started smoking. If the chips haven't started smoking by the first hour, turn up the heat to MEDIUM so that the flames reach the holes in your chip baskets easier. Keep up the heat until you see the chips start to smoke and then turn it back to LOW. If the chips start to flame, use a couple of quick squirts from the sprayer to knock the flames down. Once you get a good base of coals, it'll be easy to just add to them later.
After the first hour, it should be smoking nicely. Add some more wet wood chips and just let it go. Resist the temptation to open the grill lid! You need to keep the heat inside as much as possible. You can open the lid once every hour to add more wood chips and to make sure that the level of liquid in the drip pan remains at about 3/4 full.
Timing how long to cook it is based upon the size of the bird. I used a 17lb turkey and the overall cooking time was approximately 9 hours. So about 30 minutes per pound is a good rule of thumb. As you get near the end of cooking time, check the temperature of the turkey with a thermometer. Stick it into the meat of the inner thigh. The temperature should be between 170-180 and the juice should run clear, not pink.
Here's a shot of my finished bird. I hope yours comes out as delicious, crispy and golden brown as mine!