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If you are someone who enjoys cooking, you’re likely to have crossed paths with a pressure cooker. Even if you’re not planning on becoming a “home chef”, the convenience that pressure cookers provide may still have drawn you to them.

Pressure cookers are incredibly convenient and great at cutting down cooking time, especially when it comes to cooking meat and legumes, which are not only harder but also trickier to cook well. But despite their advantages, many people hesitate to use them because they are intimidating.

One of the things that people feel uncertain about when using a pressure cooker is deciding on how much water or liquid to put in. And today, we’re here to help you learn all about it. But first, it’s important to share a little bit about how pressure cookers work and whether there are significant differences in the amount of water you need based on the type of pressure cooker you’re using.

How Do Pressure Cookers Work?

The Science Behind Pressure Cookers

The science behind pressure cookers is actually very basic. Simply put, pressure cookers utilize the combined power of steam and high pressure to speed up the cooking process. Heating the pressure cooker causes the water inside to evaporate and turn into steam, and the air-tight lid prevents the steam from escaping, which increases the inner pressure of the cooking chamber. The high pressure inside the chamber raises the boiling point of the cooking liquid, allowing higher heat exposure, which, in turn, cuts down on the cooking time by a large margin.

According to an article by Michigan State University, a traditional pressure cooker can cook the food at around 250 degrees Fahrenheit (121 degrees Celcius), while the boiling point of water under normal pressure is 212 degrees Fahrenheit (100 degrees Celcius). Some modern pressure cookers can achieve even higher boiling points and therefore can cook even faster. The math is very simple: the more you allow the liquid to heat up at a higher temperature without boiling, the faster the cooking time you’re going to get.

The Parts of a Pressure Cooker

​​To ensure safety in the kitchen when you’re cooking it’s important to be familiar with the parts of your average pressure cooker and know what these parts do.

In a traditional pressure cooker, the cooking chamber itself is usually made out of stainless steel or aluminum. The lid or the cover of the chamber usually has a safety valve to ensure that the internal pressure of the chamber doesn’t go above the chamber’s capacity, preventing the cooker from exploding. A rubber piece is usually placed around the lid to prevent the steam from leaking.

In addition to these parts, electric pressure cookers usually contain a secondary chamber placed inside the outer chamber, where the food is actually contained. These pressure cookers often also contain a condensation collector part that is attached to the outer chamber of the appliance.

And lastly, even though it’s not an essential part of a pressure cooker, most modern stovetop pressure cookers also include a digital timer attached to the lid.

Types of Pressure Cookers

Now that we have a general understanding of how pressure cookers work, let’s take a look at what kind of pressure cookers there are and the main differences between them.

Fundamentally, there are two types of pressure cookers: traditional stovetop and electric. Even though stovetop pressure cookers are the more established type, as they have been around for a while and are probably more well-known, electric pressure cookers like the Instant Pot have brought pressure cookers back into the spotlight.

Stovetop pressure cookers are exactly what the name suggests: they need a heat source to work. Despite being quite straightforward, they are the type that requires the most diligence to use because they lack certain safety features that most electric pressure cookers have. Beginner cooks may want to be more cautious.

On the other hand, electric pressure cookers like the Instant Pot don’t need a heat source — they need an electric outlet to plug the device in instead. These appliances are much easier to use and therefore more beginner-friendly, as many of them have automatic cooking modes for different types of food.

You can read our Pressure Cooker Reviews to find out more about various models of pressure cookers.

The Basics of Using a Pressure Cooker

Now that we’ve established the basics of pressure cookers, we can finally get to learn about using one!

Learning how to use a pressure cooker boils down to knowing how much liquid you need to add in and what you need to do to make sure you’re using it safely.

Here are some general points on using a pressure cooker that will help you get the best out of your cooking experience.

How Much Water to Put in a Pressure Cooker?

When you’re cooking with a pressure cooker, avoid filling the pot with too much water. If the pressure cooker has a maximum limit, do not exceed this limit by putting in too much water or food.

Generally, leaving at least ⅓ of the pot empty is a good rule of thumb to follow. Too much liquid in the pressure cooker may clog the safety valve, which may cause your cooker to explode and it may damage your kitchen or cause burns.

It’s also good to remember that putting enough liquid in a pressure cooker is just as important as not putting too much liquid in.

To explain this simply: you need steam in order for your pressure cooker to work and for your food to cook properly. If there isn’t enough water in there, there isn’t going to be enough steam inside the pot to create the pressure needed to cook the food through.

When you’re cooking with a stovetop pressure cooker, it’s normally recommended to put in at least one cup (237 ml) of water or any other thin liquid such as chicken or vegetable stock, but of course, different recipes may call for different measurements.

The official user manual of one of the most popular electric pressure cookers, the Instant Pot, also recommends putting in at least one cup of liquid, although other models’ manuals may even suggest at least 500 ml of liquid, which converts into a little less than two cups. This is mainly due to the sizes of the pressure cookers varying from model to model, which changes the amount of liquid needed.  You can read our review of Instant Pot’s programmable pressure cooker to learn more about Instant Pot.

Don’t Forget to Add Water

It’s generally not safe to use a pressure cooker without any liquid inside, as it may lead to explosions. As a safety mechanism, most electric pressure cookers will give an error or will not start cooking unless there is a sufficient amount of liquid inside, but this is still a good rule to keep in mind.

Also, if you intend to use thickening ingredients like corn starch for thicker consistency soups and stews, be sure to add these ingredients after the pressure cooking process is done. Adding the thickening agent early will thicken the liquid inside the pot and this will allow less steam to be created and the food may not cook evenly and well.

General Safety Rules

  • Whether you use an electric pressure cooker or a stovetop one, the first step is to check if your pressure cooker is in good shape. You need to make sure that none of the parts are missing or broken, and that the rubber part that goes around the lid and the valve that lets the steam escape is perfectly clean. This will allow your pressure cooker to work properly while keeping you safe in the process.
  • Additionally, if you’re using a very old stovetop pressure cooker, you may need to set the steam valve up vertically when you start cooking, to allow the cooker to balance the inner pressure.
  • If you’re using an electric pressure cooker, make sure that the inner chamber is placed properly and do not put food or any liquid directly into the outer chamber.
  • Another important step for both electric and stovetop pressure cooker users is to release pressure at the end of cooking. Generally, you can either let the steam out manually or wait for the pressure cooker to release the steam by itself over a while. However, most recipes that involve pressure cookers will include instructions on how to release the pressure once you’re done cooking.
  • And lastly, to be on the safer side, it’s always a good idea to let the pressure cooker rest without you touching or moving it for at least 5 to 10 minutes before releasing its pressure.


Pressure cookers are very convenient kitchen tools. They can cut back on cooking time and may even create less dirty dishes than usual because you can make complete meals in them alone. But it’s always important to remember that you’re dealing with high amounts of pressure and therefore need to be extra cautious by keeping the pressure cooker in good condition.

Another crucial thing to remember is to put at least 1 cup of thin liquid like water or stock inside the pressure cooker before you start cooking and not to fill the pot too much with liquid or food.

Now that you have the basics, hopefully, thanks to this article, we hope it’ll inspire you to explore a world of delicious pressure-cooked recipes!

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