The pressure cooker has three major parts:
- The lid – where the valves and most of the safety systems reside;
- The base – where there is the logic and the heating; and
- The inner pot – where the cooking happens.
So let’s talk about the base and work our way up.
The Pressure Cooker Base
The base of the pressure cooker has the heating element, which is a ceramic disk and in the middle of the disk is a little heat sensor.
The heat sensor is there to keep track of the cooking temperature of the pressure cooker, and it’s also a safety system. If the pressure cooker detects that the temperature inside is too high it will automatically shut off.
Has all the buttons to operate the pressure cooker – including pre-set programs. It’s important to point out that different pressure cooker brands might have similarly named programs. For example, they might both have a program function called “Steaming” but it doesn’t necessarily mean that they will act the same way. In fact, Instant Pot’s steaming program steams food at “high pressure, while the Fagor LUX ‘s steaming program steams food with “no pressure”.
So, if you’re following a recipe that calls for specific buttons, you need to be aware of what’s behind those programming buttons.
The Inner Pot
The inner pot can either be stainless steel, it could be an aluminum shell coated in non-stick coating, or it can be an aluminum shell coated in ceramic.
The removable cooking bowl is where you come in on pressure cooker safety. Your manual will state, and some bowls may also state the maximum fill levels.
Some bowls may only show the “max” level for non-pressure programs – but pressure programs have an even lower fill level. While other inner bowls will actually show the markings for 2/3 and 1/2 full. Let me explain…
Maximum Fill Levels
Since most of the pressure cooker’s safety systems are on the lid, the most important thing is not to over-fill the pressure cooker and to ensure that the food inside doesn’t bubble and clog the valves. So, the way the industry has resolved this is to impose maximum fill levels.
- For foods that foam – like rice, grains and beans the pressure cooker should not be filled more than halfway with that food and cooking liquid. Because that food will bubble and make foam and the foam will rise inside the pot and it could touch the valves. Since we don’t want that – that’s why we stay at half full.
- For everything else – soups, stews, stocks, and meats you can fill the pressure cooker up to two-thirds full. Again, you don’t want to go over this because even a soup or a sauce could bubble and clog the valves. And, we don’t want that.
Read your manual carefully. Find out what the fill levels are. If they’re not already written on the inner-pot for you, you’ll need to eye-ball it and just make sure not to go over 1/2 full for beans, rice and grains or 2/3 full for everything else.
Pressure Cooker Lid
So, let’s take a look at the lid now.
Here you’ll find the pressure valve – there are two kinds.
- Floating Weight Valve – keeps the pressure in the cooker by having a weight push the steam in.
- Spring Valve – a calibrated metal spiral, an actual spring, that resits the push of the steam inside the pressure cooker.
Every time before and after you pressure cook, you want to make sure that the valve and the pipe where the steam comes through are completely free of food residue.
If you flip over the lid, you may notice that the pressure valve has a little basket – this is to ensure that food does not reach the pressure valve and needs to be cleaned occasionally. Other brands, such as the Fagor LUX, may have an additional way to keep food from getting there – such as a “false ceiling”.
The lid also has a locking mechanism. And this ensures that the minute pressure starts to build inside the cooker the lid locks closed. It’s a mechanical system, so it means that it will work even if the pressure cooker is un-plugged. If there is no electricity or even if the power goes out the lid will remain locked because it’s a mechanical system: the pressure inside pushes up a pin which locks the lid closed. There is no way to get that lid off while pressure is still inside the pressure cooker.