Note that this cooking time is for a 4-pound Boston butt pork shoulder. A general rule on barbecued pork is to cook it at about 215°F to 225°F for 90 minutes per pound.
If using a rub, you'll need to get the rub on the night before and refrigerate.
Cooking a 4 pound roast, allowing time for the barbecue to heat up and for the meat to rest once done, can easily take 9 hours, so start early in the morning if you want to have the roast done in time for dinner.
You need to keep smoke on the meat for at least 4 hours for a 4 pound roast. If the roast isn't done after 6 hours, finish it in the oven, wrapped tightly in foil to hold in the moisture.
Two rub recipes are provided here. Pick one for a 4 pound roast, or if barbecuing two roasts, try one each.
- One 4 pound pork shoulder roast, preferably Boston butt, boneless or bone-in (you can easily make two 4 pound roasts in about the same amount of time if your grill is big enough to accommodate them both)
- 5 to 6 cups of wood chips, hickory, oak, apple, or other fruit wood
BBQ Rub (enough for a 4 pound roast)
- 2 Tbsp brown sugar, packed
- 2 Tbsp white sugar
- 2 Tbsp paprika
- 1 Tbsp kosher salt
- 1 1/2 teaspoons ground cumin
- 1 1/2 teaspoons garlic powder
- 1 1/2 teaspoons chipotle chile powder
- 1 1/2 teaspoons black pepper
Santa Maria Rub (enough for a 4 pound roast)
- 1 Tbsp salt
- 1 Tbsp finely ground black pepper
- 1 Tbsp garlic powder
- 1 Tbsp onion powder
- 1 teaspoon cayenne
- 1 Tbsp dried oregano
- 1 teaspoon dry rosemary (or fresh, finely minced)
- 1/2 teaspoon dry sage
- 1/4 teaspoon sugar
The day before:
1. Prepare the rub. Mix all the ingredients for the rub together, breaking up any clumps. Taste the rub as you make it and see if you like the taste, adjust accordingly.
2. Rub the roast with the rub. Unwrap the pork roast and place it on its butcher paper or in a roasting pan, something that can catch the rub. With your (clean) hands work the rub mixture into the pork shoulder all over, including inside any crevasses you may find in a boneless roast where the bone had been. Be generous with the amount of rub.
Rewrap it in the butcher paper or wrap it in plastic and place it in a pan (to catch any liquid that may drip out), and refrigerate it overnight.
The night before:
3. Soak the wood chips. Take 3 or 4 large handfuls of wood chips (hickory, oak, apple or other fruit wood) and place them in a bowl and cover them with water to soak them overnight (can also do for an hour before using).
I think it helps to have a mix of sizes, from small chips to larger (1-inch x 2-inch) chunks. The smaller chips will get smoking more quickly, but will burn out more quickly too. The larger chunks will take longer to catch, but last well past when the smaller chips have burned themselves out.
The Day Of:
4. Bring the chilled roast to room temp. 1 to 2 hours before you start the barbecue, take the pork out of the refrigerator to come to room temperature.
Now, if you forget to do this, which I have done, you can still go ahead and BBQ it. You'll likely be finishing it in the oven anyway. It will just take a bit longer to cook.
5. Prepare your grill. Remove one of the grill grates. This will be your "hot" side, where the wood chips will go. The other side of the grill will be the "cool" side, and where the meat will be, away from direct heat.
Depending on the structure of your grill, you may want to remove the "flavor bar", the thin metal piece with lots of holes in it that sits over the burner. The wood chips will smoke more easily if they lay in a (fireproof metal or foil) container directly on the burner.
6. Place a tray of water on the grill: If there is room on your grill, place a small aluminum tray of water on the grill to help moderate the heat and help keep the roast from getting too dry. A good place to place this is on an upper rack if you grill has one.
7. Get the grill smoking. Create a double layered aluminum foil boat with a handful or two of damp wood chips in it.
Place the boat directly on the burner on the "hot" side of the grill if you can (otherwise place on the flavor bar). Turn the grill on to medium flame, cover the grill and let it heat up until the the wood chips start smoking.
You'll either see smoke coming out of the grill, or if you raise the lid, you'll see smoke coming out of the wood chip boat. You should see and smell the smoke.
You'll be replenishing the wood chips periodically for the next several hours so put more dry chips into water to soak if needed.
8. Cook roast on cool side of grill, fat side up: Once the grill is smoking, place the roast on the grill grates on the cool side of the grill, away from direct heat. If your grill has a hot spot, position the roast away from it. If there is a fatty side to the meat, put that side facing up; the fat will render over time and baste the pork.
Cover the grill, lower the flame, and let the cooking begin. The temperature you want to maintain ideally is 225°F. Try to keep it close to that temperature, within a range of 210°F to 240°F. If the temperature goes too high, the roast may dry out. If it's too low, it will take forever to cook.
9. Maintain the smoke and the 225°F temperature. This is the tricky part. You will want to maintain smoke in the grill for at least 4 hours (6 hours for a bigger roast). You will also want to maintain a cooking temperature of around 225°. So, you have to check the grill!
Check if the temperature is being maintained between 210°F and 240°F, and check to make sure the chips are still producing smoke, every half hour. About once an hour you will likely need to replenish the chip boat with more wood chips.
Resist the temptation to open the grill more than once an hour. Every time you open the grill the inside temperature drops and you increase your overall cooking time.
I found the best way to check the temperature, since I don't have a gauge in the grill itself, is to put an instant read meat thermometer into an opening in the hood on the meat side (cool side) of the grill, and just keep checking it. Make sure sensor tip of the probe is not touching the meat itself.
You want to avoid opening up the hood too often, because every time you do that, you lose heat. Of course, if your gas grill gets too hot, opening the hood can cool it down quickly.
Expect a minimum cooking time, if you have been diligent at maintaining a 225°F, of 90 minutes per pound. So if you are cooking a 4 pound roast, total cooking time will be at least 6 hours (and easily more). An 8 pound roast will take at least 12 hours of cooking time.
If you want to cook 8 pounds of pork shoulder more quickly, I recommend starting with two 4 pound roasts, spaced on the grill a few inches apart, which will cook in just a little more time than an 8 pound roast.
10 Reposition the roast: After 2 or 3 hours, during one of your hourly opening of the grill to refresh the wood chips, reposition the roast so that the side that was closest to the heat is now furthest from the heat.
11. Test internal temperature of meat. After about 5 hours, start taking the pork's internal temperature: You can eat it at 165°F, but if you are making pulled pork the meat needs to be ideally 195°F.
12 Remove from heat, let rest: When the meat reaches 195°F, remove it from the heat, tent it loosely with foil over a cutting board (to catch the juices) and let it rest for at least 30 minutes, and preferably 1 hour.
If after 6 hours of cooking, if the meat hasn't reached 195° internal temp (usually after 6 hours, the internal temp on my roasts is about 155°F), my recommendation is to remove it from the grill and finish in the oven.
To finish in the oven, wrap the roast in aluminum foil to help prevent it from drying out in the oven, and place it in a roasting pan, in a 300°F oven.
Cook until the internal temperature of the roast reaches 195°F. If your starting internal meat temperature is 150°F or so, this can take anywhere from an hour to two hours.
When it reaches temperature, remove the roast from the oven and let rest for at least 30 minutes, up to an hour.
13. Pull the pork. Pull the pork with 2 forks. Only now do you add any barbecue sauce (and any accumulated juices) to the meat. Taste it first! It might not need sauce at all, and if it does, add only a little at a time. One of the biggest sins of barbecue is to over-sauce perfectly good meat.