In a small bowl, combine brown sugar, salt, paprika, chili powder, oregano, garlic powder, mustard, cayenne pepper, cumin and pepper. Season pork with brown sugar mixture.
Heat canola oil; working in two batches, add pork and cook until evenly browned, about 3-4 minutes.
Stir in chicken stock and 4 tablespoons vinegar, scraping any browned bits from the bottom of the pot. Select manual setting; adjust pressure to high, and set time for 40 minutes. When finished cooking, quick-release pressure according to manufacturer’s directions.
Remove pork shoulder from the Instant Pot® and shred the meat using two forks; stir in remaining 2 tablespoons vinegar and season with salt and pepper, to taste, if needed.
Serve immediately with your favorite bbq sauce.
Notes
Cut the pork into 3-inch chunks. Using smaller pieces of pork will keep the cook time to a minimum and allow even cooking, ensuring juicy, tender, fall-apart pulled pork.
Sear the pork. Searing the pork first will add all the extra, deeper flavors here, sealing all the juices inside.
Work in batches. An overcrowded Instant Pot® can lead to uneven cooking and poor browning. Work in batches to maintain high heat for a good sear and crispy crust on each pork piece.
Use good-quality stock. The better quality your stock, the better your pulled pork. Many brands love to pack in the salt so always opt for unsalted or a lower-sodium variety. Homemade stock is even better.
Freeze without the sauce. For best results with leftovers, freeze the leftover shredded pork without the BBQ sauce to preserve the texture and prevent sogginess, adding BBQ sauce when reheating.