The reason you can set the pot for zero minutes is that the cooking process begins to happen as soon as you turn it on. While the pot is building pressure it is creating heat and steam which is cooking the food.u003cbr/u003eu003cbr/u003eFor some foods, such as broccoli, it doesn't need any further cooking after the pot comes to pressure, the steam created during pressurization is enough. This is why it can be set for zero minutes.