If it's bigger, steam it for 30 minutes or more. After 20 minutes of steaming, use chopsticks to pierce the sweet potatoes a few times, and if they penetrate easily, they are cooked.

Generally, when steaming sweet potatoes, first use high heat, wait until the water in the pot boils, reduce the fire to medium-low heat, and then steam for ten to fifteen minutes, depending on the size of the sweet potatoes, the big ones will steam longer, the small ones will steam faster.