How do I use a pressure cooker safely?
The fill limits, the checks before every use, and the foods that foam and block the valve.
- Difficulty
- intermediate
- Time
- 20 min
- Read
- 3 min
- Safety
- warning
Short answer
Never fill it more than two-thirds, or half for anything that foams. Check the seal and both vents are clear before each use, always include enough liquid to generate steam, and never try to open it until the pressure has fully dropped.
Modern pressure cookers, stovetop and electric, have several independent safety systems and are very safe when used correctly. Almost every accident comes from overfilling, a blocked vent or forcing the lid.
Safety
Step by step
- Check the seal before every use.The rubber gasket should be soft, clean and free of splits. A perished seal leaks steam and the cooker never reaches pressure. Replace it every year or two.
- Check the vents are clear.The main pressure valve and the safety valve. Hold them up to the light — food residue blocking either is the most dangerous fault a pressure cooker can have.
- Never exceed two-thirds full.The space above the food is where the steam lives. A cooker filled to the brim has nowhere to build pressure and food can be forced into the valve.
- Use the half-full limit for foaming foods.Dried pulses, rice, pasta, porridge, apple sauce, anything starchy. They foam vigorously and the foam blocks the valve. Adding a tablespoon of oil reduces it.
- Always add enough liquid.Usually at least 250ml, or whatever the manual says. Pressure cookers work by generating steam, and a dry cooker overheats and scorches.
- Bring it up to pressure and then reduce the heat.On a hob, high heat until the indicator rises or the valve hisses, then down to the lowest setting that maintains it. A cooker roaring at full heat is just boiling liquid away.
- Start timing from when pressure is reached.Not from when it goes on the hob. The heating-up time is not cooking time and recipes assume this.
- Choose the release method deliberately.Quick release for vegetables and fish; natural release for meat, pulses and anything liquid. Quick-releasing a foaming pot sprays hot liquid out of the valve.
- Never force the lid.It will not open until the pressure has genuinely gone, and that interlock is what keeps you safe. If it will not turn, it is not ready.
- Clean the lid and vents after every use.Take the seal out, wash it, and check the valves are clear. This is the maintenance that prevents the serious faults.
Tips
- Two-thirds full, or half for anything starchy. This one rule prevents most problems.
- If the lid will not turn, the pressure has not gone. Never force it.
- Replace the gasket every year or two — a perished seal is the commonest reason a cooker stops reaching pressure.
Common mistakes
- Filling the cooker to the top — There is no headspace for steam, so food is pushed up into the pressure valve as it boils, blocks it, and the cooker loses its primary pressure control. It is the single most common cause of pressure cooker accidents.
- Quick-releasing a pot of pulses or porridge — The sudden pressure drop makes the liquid boil violently and it foams up and sprays out of the valve, coating the kitchen and scalding anyone nearby. Foaming foods need a natural release.
If it doesn't work
Will not come up to pressure
Cause: Perished seal, lid not locked, or not enough liquid — Fix: Check the gasket, reseat the lid, and add liquid to the minimum in the manual.
Steam escaping around the lid
Cause: Seal dirty, damaged or misaligned — Fix: Take it off and refit it, or replace it if it is split or hard.
Food burnt on the base
Cause: Not enough liquid, or heat too high — Fix: Add liquid to the minimum, and reduce to the lowest heat that holds pressure.
Liquid spraying from the valve
Cause: Overfilled, or foaming food quick-released — Fix: Turn the heat off, let it release naturally, and reduce the fill level next time.
Lid will not open
Cause: Pressure still inside — Fix: Wait. Never force it. Run cold water over a stovetop cooker's lid if the manual permits it.
Questions people ask
Are pressure cookers dangerous?
Modern ones have multiple independent safety systems — a locking lid, a primary valve, a secondary safety valve and a gasket release — and are very safe. Accidents almost always trace to overfilling, a blocked valve or forcing the lid.
Can I open a pressure cooker to check the food?
Only after fully releasing the pressure, which takes a few minutes at minimum. This is the main disadvantage of pressure cooking — you cannot taste as you go, so seasoning is judged at the end.