Indicators change color gradually across a pH range, and it is common for one of the indicator's forms to be colorless. Since indicators are weak acids, care should be taken to avoid adding too much indicator (more than 3 to 4 drops per 100-mL) to a solution of acid or base.
Roast your pork shoulder in the oven at 350 degrees F for 30 to 35 minutes per pound for a nice slicing roast. At this temperature, a 6-pound pork shoulder will require 3 to 3 1/2 hours to roast. Check for doneness by placing a meat thermometer into the roast at the thickest point. Be careful not to touch the bone.
Set the meat on a rack set into a roasting pan. Roast for 20 minutes, and then reduce the heat to 325 degrees F. Continue to cook until an instant-read thermometer inserted into the shoulder reads 185 degrees F, about 4 hours.