The following recipe consistently produces fabulous ribs, but be sure to follow each step carefully. What you are looking for with ribs is tender meat, but still a little chewy. The meat should stick to the bone, but fall off cleanly with a little tug.
There are two main kids of pork ribs: baby backs and spares. For spares, you can cook the entire rack, or you can trim off the top part to get St. Louis style ribs. This recipe is best with baby backs or St. Louis-style spares. For both types, you should always trim the membrane from the back of the rack before cooking. See this link for a discussion on St. Louis style ribs and a photo illustrating the removal of the membrane. I like to use a paper towel to help grip the membrane:
If you buy your ribs at Costco, you can either buy baby backs or pre-trimmed St. Louis style spares. Personally, I prefer spares. Costco ribs generally come in a rack of three per package, but sometime they sell two per pack. One rack feeds ~3 people.
Also, when you buy the St. Louis-style spares, there is often a big chunk of fat and meat on one end of the rack on the meaty side. I like to trim that off with a filet knife (it is mostly fat). I also trim off any additional silvery membrane and big chunks of fat from the meat side. This helps the rub and smoke better penetrate the meat.
1) Apply a liberal amount of your favorite rub to each rack. You can do this just before smoking if you like or you can rub and wrap and put them in the fridge for a few hours or overnight. I think it is better to do right before because the salt can extract water from the meat.
2) Put the ribs in the smoker at the smoke setting (180 degrees) for 1.5 hours. I prefer to use mesquite pellets but you can use any type you like. The smoking phase is relatively short so mesquite gives it a nice strong flavor but it isn’t too strong.
3) Place each rack in foil. I like to use the heavy duty foil from Costco and I normally use two sheets because it is easy to puncture one sheet and you don’t want to lose your moisture. Add a liberal amount of apple juice (0.75-1 C per rack) and fold and seal tightly. Put back on the grill and crank up the temp to 275 deg and cook for 2 hours.
4) Remove from grill. Unwrap the foil and drain the juice. Using a basting brush, slather your favorite BBQ sauce on both sides of the rack and return the racks to the grill (without foil). Turn the temp down to 225 degrees and cook for an additional 30-45 minutes.
5) Remove racks from grill and tent in foil or under a large roasting pan lid for 15 minutes prior to serving.