Why pressure cooking is faster?

Published On: February 6, 2024

Modern multi cookers like the Instant Pot have grown in popularity in recent years. One of the many reasons is that they allow you to prepare meals more quickly than if you were cooking on the hob, and far more quickly than using your slow cooker. In fact, one of the selling points of this way of cooking is that you can achieve “slow cooked textures in pressure cooked times”. That’s not to say that a multicooker doesn’t slow cook too, because it does, but the appeal of the multicooker is that with one of the many cooking options being pressure cooking, you also have the option not to plan what you’re going to cook too far in advance. What is indisputable is that pressure cooking is a faster way to cook but what many people are unsure of is how a pressure cooker works and why it is faster than cooking either using a slow cooker or on the hob.

Firstly, a little bit of physics. We all know that hot air rises. When you cook in a regular pot on the hob, a lot of the heat escapes. Once moisture in the food turns into steam, which happens at 100°C, a lot of that moisture escapes through evaporation. However, in a pressure cooker, there’s nowhere for that hot air and steam to go. It is trapped! Because the hot air and steam are trapped, a pressure cooker allows you to heat the moisture i.e. steam and water, above its normal limit of 100°C and the trapped hot air and moisture within the food speeds up the cooking process.

In other words, the moisture surrounding the food reaches higher temperatures than it would without the pressure which speeds up the chemical processes involved in cooking. It also doesn’t cause the food to dry out like it would in an oven or on the hob because the moisture has nowhere to go. Slow cooking also uses heat and moisture to cook food but over a much longer period, often half a day. To give you some idea of the time it takes to cook the same food in an Instant Pot on high pressure compared to both a slow cooker and on the hob, check out these comparison tables:

cooking time table

Note: Each appliance will differ, but these are the general cooking times that you can expect from the different cooking devices.

Not only does pressure cooking save you time when cooking from scratch using raw, uncooked ingredients, it also lends itself to cooking even frozen food from scratch. People sometimes worry about the safety of cooking straight from frozen, especially raw meat, or poultry. In fact, pressure cooking is one of the safest ways to cook from frozen. It’s safer than slow cooking frozen foods. That’s because between 8°C and 60°C i.e. “the danger zone” (according to the Food Standards Agency), pathogens in uncooked meat may be allowed to produce toxins that can persist even after the temperature gets high enough to kill the pathogens themselves. Just killing the pathogens won’t make the food safe if they’ve already created heat-stable toxins. Pressure cookers are therefore ideal for cooking from frozen because they do a great job of getting foods through the temperature danger zone quickly.

Not only is pressure cooking using your multicooker a great way to achieve succulent and moist textures, retain great flavour but it’s also faster than other methods such as the slow cooker and cooking on the hob. It also lends itself to cooking food from frozen too. It’s easy to see why pressure cooking is becoming so popular.

By Jenny Tschiesche (BSc (Hons) Dip (ION) FdSc BANT)