[sph]

30 minutes is not very useful. The good thing about pressure cooking is 1 hour is more or less equivalent to 2.5 hours in a regular stove.

Cook a stew for 2 hours in a pressure cooker and even the toughest meat will melt like butter in your mouth.

[vladvasiliu]

I don't know what the limit is on pressure-cooking, the 30 minutes is for non-pressured "slow cook" mode. It won't engage the "pressure-cooking" mode if the lid is not secured in place. I never needed to pressure-cook for more than 30 minutes at a time, though. The longest recipe I had was, IIRC, 30 + 15 minutes. The recipe said to put dry beans in, pressure-cook for 30 minutes, release pressure, add sausage, cook for 15 more minutes.