Trim off excess fat and any silver skin. If the fat cap is on the loin, you can leave it on and score in a ¼" crosshatch pattern.
Drizzle on the oil and apply the salt and dry rub. Cover and refrigerate.
Smoke the Pork Loin
Remove the pork from the refrigerator to temper 30 minutes before cooking. Insert a remote probe thermometer.
Set up your smoker for indirect heat cooking and preheat to 225° F with apple wood for smoke (see alternative woods in notes).
Place the pork loin in the smoker and smoke until an internal temp reaches 135°F to allow for carryover cooking, which will result in a finished temperature of 140 to 145° F for medium. Plan on approximately 1 ½ to 3 hours, depending on the size of the roast.
Remove from the smoker and rest on a cutting board for 15 to 20 minutes. Slice against the grain and enjoy!
Season the pork at least 1 day and up to 2 days in advance for best results.
If your pork is "enhanced," this means salt has been added and you will want to reduce the amount of salt you use.
Use 1 teaspoon Diamond kosher salt (or ¾ teaspoon Morton kosher salt) per pound of pork loin.
Best woods for smoking pork: Apple is my favorite, but you can also use cherry, maple, pecan, hickory or any combination of them.