Place the green beans in a colander and rinse well. Shake off excess water, then snap or trim off the stem ends. You can trim both ends of the beans if desired.
If using a 3 or 6-quart pressure cooker, pour 1 cup of cool tap water into the inner pot. If using an 8-quart Instant Pot, pour 1½ cups of cool tap water into the inner pot.
Place a metal trivet or steamer basket inside the inner pot over the water. Add the prepared green beans to the basket, or carefully stack them on the trivet.
Close the lid, being sure the vent knob is sealed or locked. Using the manual or pressure cook button, set the cooking time to 0 minutes on high pressure. For softer green beans, set the cooking time to 1 minute.
Once the cooking time has elapsed, immediately do a quick release of pressure. To do this, use a long utensil and carefully knock the vent knob from the sealing to the venting position. Stand back to prevent being burned by the steam.
Remove the green beans from the pressure cooker. Season and serve immediately.
Notes
What If Your Instant Pot Doesn't Adjust to 0 Minutes? Set the cooking time to 1 minute on High Pressure. For crisp-tender green beans, press Cancel as soon as the Instant Pot beeps to indicate it has reached pressure, then immediately perform a quick release. For softer green beans, let the 1-minute cook time finish before performing a quick release.Variety of Green Beans: This method works with fresh or frozen standard green beans, also called string beans or snap beans. It also includes tested timing for frozen haricots verts. Yellow or purple wax beans can be cooked using the timing for similarly sized green beans.Frozen Green Beans: Cook from frozen over water as directed using the following times:
Frozen Cut Green Beans: 2 minutes with quick release of pressure
Whole Green Beans: 1 minute with quick release of pressure
Frozen Thin Green Beans (Haricot Verts): 0 minutes with quick release of pressure
Increasing Quantity of Beans: This timing is based on using 1 pound of fresh or frozen green beans. To double or triple that amount, keep the amount of water the same, and increase the cook time by 1 minute. You can cook up to 3 pounds of green beans in the Instant Pot. Storage: Store any leftovers in an airtight container for up to 4 days in the refrigerator. Enjoy cold or reheat briefly in a skillet or microwave just until warm to avoid overcooking them.