Video: How Does A Pressure Cooker Work?

How does a Pressure cooker work?

How does a pressure cooker work…well steam and pressure combined make the magic happen. Put the two together and you have cooked food in no time at all.

We need to look at basic science for an explanation to why this happens.

The science behind pressure cookers

There is a reason why we cook in water. It is a better conductor of heat than air. Therefore, energy is transferred better through water than it is through air. By heating the water, you are transferring energy and therefore cooking the food.

Under normal atmospheric conditions, water boils at 100°C. In high areas like a top of a big mountain, water boils at lower temperatures. The opposite is the case in a pressure cooker. Water boils at a much higher temperature. This is through the pressure increase in the cooker.

The water gets much hotter and as it is sealed in, the steam it produces is also much hotter. It therefore gets to work cooking the food.

The pressure in the cooker also makes a big difference. So how does a pressure cooker work?…It is literally pushing the heat into the food. The dual effect means your food cooks much faster and the moisture retained within the cooker means that the food does not lose its moisture.

How does a Pressure cooker work? We explain it with basic science

What does a pressure cooker consist of?

A pressure cooker has a main body, a ring that acts as a seal, a lid that is lockable onto the main body and a valve incorporated onto the lid. Put together, they produce a simple but wonderful process.

The ring acts as a seal and traps the stem within the cooker. This means that pressure can build up within it. A failure in the seal will mean that it will not work.

The valve stops the overbuild up of pressure. If it did not have a release, it can be incredibly dangerous leading to a possible explosion.

Do you have to put water in a pressure cooker?

Yes, it is based on creating pressure through steam. It is the higher boiling point and the higher temperature of the steam that forces the heat into the food to cook. You can use more water, but never less than the minimum amount.

Is it healthier to cook in a pressure cooker?

The simple answer is yes. The shorter cooking time means more nutrients are preserved within the food.

Why would you use a pressure cooker?

It reduces the cooking time significantly while retaining a greater amount of nutrients in the food when compared to normal cooking. The cooking process also means that tougher food such as a tough cut of meat can tenderise very quickly when compared to normal cooking methods.

 Advantages of a Pressure cooker

  • Reduced time to cook
  • Less energy used overall through reduced cooking time
  • Less water used
  • Reduced amount of nutrients lost
  • Food tenderises quickly
  • It can be used at any altitude

Disadvantages of pressure cookers

It takes time to learn

It isn’t as simple as just following a recipe. You need to make adjustments to recognise that water does not evaporate. Therefore, more liquid is retained within the dish.

Is a slow cooker the same as a pressure cooker?

They are in fact the opposite. A slow cooker as the name suggests cooks the food very slowly over an extended period of time…often the whole day. A pressure cooker on the other hand cooks food very quickly, a fraction of the cooking time over normal cooking methods.

Timing is important

You do not have the option to see whether your food has cooked as the lid is sealed. This retains the pressure within the cooker. If you remove the lid, you lose all the steam and the pressure within it. Timing is therefore very important and you must follow the instructions if you do not want your food to be wasted.

Overcooking is a real threat

Under normal cooking conditions, leaving food to cook a couple of minutes longer may not be ideal but it is not a major disaster. This is not the case with pressure cooking. It can have a major impact in a pressure cooker given how quickly it cooks.

You are therefore advised to follow recipes that are designed specifically for pressure cookers.

Learn about slow cooking…the advantages and disadvantages


In this post you will have learnt how does a pressure cooker work. They are wonderful pieces of equipment that can make a major impact on how you do things. They may seem daunting at first but follow the recipes and marvel at the amazing results.

Let us know in the comments what your experiences are with pressure cooking…what you cooked, how long it took and how it tasted. I would love to hear from you.



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