For home cooks that are just looking to make dinner, and not restaurant-quantity stock: bigger is not better. We recommend getting the smallest pressure cooker to fit your needs because a bigger the pressure cooker will take longer to reach pressure, will need more liquid to get there and it will be bulky to both clean and store.
Step One
More material - A larger pressure cooker will have more metal and that metal will take more time to heat up – time you’ll be waiting for it to reach pressure .
Step Two
More liquid - As pressure cooker size increases so do the minimum liquid requirements – while a small 2qt pressure pan only needs about 1/2 cup of liquid (or less) to reach pressure a much larger 12qt pressure cooker needs two cups (or more)! The same piece of meat that braises in the smaller pressure cooker can only be boiled in the larger one - limiting the cooking techniques that can be achieved.
Step Three
More work - On the more practical side of things, a giant pressure cooker is going to be tricky to wash and store. Depending on your sink and water tap configuration it can be quite a challenge to wash. Instead, a 6-quart cooker with a dish-washer safe base can easily slip into the bottom rack.