1. Preheat the grill to a medium temperature. If using a charcoal grill, wait to coals are about white.
2. Place the sweet potatoes on the highest rack.
3. Turn a quarter turn every 10 minutes.
4. Check for tenderness after 40 minutes. (If there are still hard spots, continue to turn every 5 minutes until done).
5. Serve with butter and a little paprika or with butter and brown sugar.