2. In addition, if you are not sure whether the sweet potato is steamed, you can insert it from the surface of the sweet potato with chopsticks or forks. If the sweet potato is easy to insert, it means that the sweet potato has been steamed. If the sweet potato can't be inserted in the middle, there is still a hard core in the middle. It takes 3-5 minutes to steam to judge whether it is cooked or not.