When the fork twists. I wrap it in foil about 160. And around 190 I start sticking the fork in an twisting to see if it twists. When I wrap in foil , I normally pour some apple juice around it as well. When I pull it, I leave it wrapped and rest for 2 hours wrapped in towels. Open your package pull the pork , pour the left over juices over the meat and enjoy ! Damn. I'm hungry.