For a 3 or 6-quart pressure cooker, pour 1 cup of cold/room temperature water into the inner pot. For an 8-quart Instant Pot, pour 1.5 cups of cold/room temperature water into the inner pot. Add trivet to pot.
Scrub sweet potatoes and pierce several times with a fork or knife. Place potatoes on the rack and seal the Instant Pot.
Cook on high pressure for 18 minutes for small potatoes, 22 for standard, 27 for large. To set cook time, hit manual or pressure cook and then adjust the time using the +/- buttons for the right amount of cook time. (Be sure the Instant Pot is set to high pressure, not low pressure. If low pressure is lit up, hit pressure or pressure level to change to high pressure.)
Allow pressure to release naturally for 10 minutes before releasing pressure manaually.
Cook time is determined by diameter or width of sweet potatoes. Select sweet potatoes that are similar in size. This way they will pressure cook in the same amount of time.
18 minutes on high pressure for small sweet potatoes (2 inches in width or diameter)
22 minutes on high pressure for medium sweet potatoes (2-3 inches in width or diameter)
27 minutes for extra large sweet potatoes (3-4 inches in width or diameter)
Pierce sweet potatoes several times before cooking--this will prevent the rare occurrence of a sweet potato bursting in the Instant Pot.
NEVER use warm water as this will change the amount of time it takes for the Instant Pot to come to pressure, which will change the cook time!
Always use the trivet to keep the sweet potatoes from sitting in the water--this will keep the sweet potatoes from becoming soggy.