Why a Pressure Cooker Cooks Food Faster

Making chili from dried beans, hummus from dried chickpeas, or a scrumptious meat stew. When you’ve got lower than an hour, they’re a no go. You want hours. Until…

You occur to personal a strain cooker!

A strain cooker speeds issues up significantly. Permitting you to make them inside an hour. However how come strain makes meals cook dinner quicker?

Strain cooking = Excessive-temperature cooking

Strain cooking known as strain cooking, since you’re actually cooking meals underneath strain. Nonetheless, it’d simply as nicely be known as “high-temperature cooking”, as a result of, successfully, that what’s occurring.

Meals doesn’t cook dinner quicker due to the excessive strain per se, it cooks quicker due to the impact that strain has on the temperature within the cooker!

Water boils at 100°C (212°F)

At sea degree, water boils at 100°C (212°F). At its boiling level water evaporates and turns from a liquid right into a fuel. This takes a while, however when you go away a pot of boiling water on a range for a while, it received’t take that lengthy earlier than all of the water has left the pot.

As a result of water transitions from liquid into fuel there’s no method to warmth up your soup, stew, or rice dish increased than this temperature. First, the water must evaporate, solely then are you able to improve the temperature additional.*

Cook dinner quicker at increased temperatures

If we’d have the ability to cook dinner at increased temperatures, cooking would go quicker. All kinds of processes happen quicker due to a rise in temperature. It is because the molecules that make up your meals transfer quicker at increased temperatures. They’ll transfer to different areas quicker, work together with one another quicker, and extra.

So how can we improve the cooking temperature?

Cooking within the mountains & a strain cooker

When you go up within the mountains you’ll discover that water boils at a decrease temperature. That’s as a result of the encircling strain of air is decrease up within the mountains than it’s at sea degree. Because of this, the strain on the water is decrease and it turns into simpler for water molecules to flee the water and type a fuel. That’s, the boiling level, the temperature at which water transitions from a liquid right into a fuel, goes down.

The other although is true in a strain cooker. In a strain cooker, you construct up a excessive strain that’s increased than in a daily pot or pan. The excessive strain within the strain cooker presses down on all of the liquid water molecules. This makes it tougher for water molecules to flee the liquid and type a fuel.

Because of this, the boiling level of water in a strain cooker is significantly increased.

Relying in your mannequin of strain cooker, the boiling level of water could improve as much as about 120°C (250°F). That’s significantly increased than it might usually be. And it’s why strain cooking cooks your meals a lot quicker than a daily pot in your stovetop would!

10°C hotter is ~2 occasions quicker

So how a lot quicker are you able to cook dinner? That’s laborious to say exactly, it is determined by the precise meals you’re cooking. However, as a tough guideline, needless to say for each 10°C improve, cooking occurs roughly twice as quick.

Why? As a result of chemical reactions happen roughly twice as quick for each 10°C improve. The Arrhenius equation, which describes the speed of chemical reactions, states this. In fact, cooking isn’t simply chemical reactions, so this system doesn’t maintain up completely, nevertheless it’s the most effective science-based estimate there may be.

How strain builds in a strain cooker

No matter the kind of strain cooker your have, stovetop or electrical, it’s core mechanism is similar.

When you fill and shut your cooker, you’ll begin heating the contents, whether or not that’s beans + water, the substances for a soup, or possibly a inventory. As soon as the water in your pot is boiling, water begins to evaporate. Nonetheless, that water vapor can’t go away the pot. It’s locked inside.

This causes the strain within the pot to extend. The water vapor presses on the partitions of your cooker. The warmer it will get, the upper the strain will get. So long as the vapor can’t escape and so long as you proceed to warmth the strain will carry on rising and consequently, the temperature within the pot rises!

There’s a restrict to the utmost strain

Nonetheless, we don’t need it the strain to get too excessive both. Regardless that a strain cooker is made up of a robust container, with a nicely secured lid, it may well solely deal with a lot strain. If the strain will get too excessive, it would explode, not a fascinating state of affairs for positive!

It’s why strain cookers include aid valves. When the strain inside a strain cooker exceeds a sure strain, the cooker will routinely set free some steam. By letting a few of the water vapor escape, the strain goes down a bit of, defending the pot from exploding.

Most strain in strain cookers

So how sizzling can it get in a strain cooker? Most significantly, that is determined by the mannequin of strain cooker you personal. Theoretically, we may construct strain cookers that may deal with extraordinarily excessive pressures, nevertheless, these would not match comfortably in your kitchen and could be method to heavy to deal with. The partitions merely should be too thick to carry all that strain inside.

As an alternative, most strain cookers are rated at a strain that enables for them to nonetheless be carried round simply.

15 psi provides +20°C

The strongest strain cookers, this contains many stovetop fashions and better rated electrical cookers, can deal with pressures as much as 1 bar (15 psi). That’s, the strain can be 1 bar increased than the encircling air strain.

At sea degree, that might end in a boiling level of water of 120°C (250°F).

11 psi provides +16°C

Barely decrease rated fashions, together with many electrical strain cookers, have a decrease most strain of roughly 0.75 bar (11 psi). That offers a water boiling level of 116°C (241°F).

That distinction could sound minor in comparison with the upper rated cookers. However, the connection between temperature and charges is exponential, so even just a few levels has a substantial impression on cooking charge.

Low, excessive Pressures for InstantPot

The InstantPot is likely one of the most well-known electrical strain cookers. It undoubtedly was one of many first reasonably priced fashions and have become extremely standard. InstantPots usually have at the least 2 totally different strain settings: high and low. I’m not too positive of the use instances of the low setting (I personally by no means use it), as a result of why would you utilize a strain cooker to hurry issues up solely to then gradual issues down once more?

That mentioned, the strain settings for InstantPot fashions are as comply with:

Excessive Strain: 10.2 to 11.6 psi (0.7 – 0.8 bar) – boiling level water ~115-117°C (239-242°F)
Low Strain: 5.8 to 7.2 psi (0.4 – 0.5 bar) – boiling level water ~109-111°C (229-233°F)
There’s additionally a mannequin that may attain 15 psi, however most can’t get that prime.

Electrical vs stovetop strain cookers

Each electrical and stovetop strain cookers work just about the identical manner. The one distinction is that electrical strain cookers regulate their strain and cooking program routinely. It’s just about ‘set it and overlook it’. You may set the length of the cooking program, and it’ll cease routinely as soon as it’s performed.

Stovetop strain cookers nevertheless want a bit of extra expertise and ‘handholding’. Whereas electrical strain cookers have sensors that decide whether or not extra warmth it wanted, it’s essential to do that your self with a stovetop cooker. By regulating the quantity of warmth you place in your pot by way of your stovetop, you management how briskly strain builds up.

What to make in a strain cooker

Discover how we’ve been discussing water on a regular basis on this article? That’s as a result of strain cookers are made to cook dinner meals that accommodates loads of water. You want the water to evaporate and construct up strain. It’s why soups, stews, rice, beans, all work nice. Strain cookers should not meant for frying or very dry dishes.

Desserts?!

Sure, you may make desserts and puddings in a strain cooker. To make them, you’ll want so as to add a layer of water on the backside of your pot. You merely place the cake or pudding on high. Do ensure the cake is correctly lined so water and steam doesn’t get in. Additionally, needless to say you’re cooking the cake in a really humid surroundings. So, don’t anticipate crunchy dry crusts. It’s why cheesecakes work significantly nicely as an example.

Dulce de leche / Caramel sauces

It’s surprisingly simple to make dulce de leche, or caramel sauces usually for that matter, in a strain cooker! Whereas making them in a pot usually requires loads of stirring and ready, making them in a strain cooker is manner much less effort.

Gradual cooked meats

Stews, ribs, and different meat cuts that might usually require hours to cook dinner will be made in a strain cooker nicely throughout the hour. In these meat cuts collagen wants to interrupt down so as to make them tender. In a strain cooker this merely occurs a lot quicker.

*When grilling or frying you possibly can create temperatures increased than 100°C (212°F). Nonetheless, your meals solely turns into this sizzling as soon as sufficient water has evaporated. More often than not, it’s simply the surface of the meals that will get that sizzling.

Sources

Engineering Toolbox, Water boiling level at increased pressures, hyperlink, visited Oct-2023; a instrument to calculate the water boiling level at increased pressures

InstantPot, Cooking occasions, hyperlink

Jopson, Marty. The Science of Meals: An Exploration of What We Eat and How We Cook dinner. United Kingdom: Michael O’Mara, 2017, Part: Underneath strain. hyperlink

B. Srilakshmi, Meals Science, New Age Worldwide Publishers, 2003, p.18-19, hyperlink