Everyone has used that classic phrase of indignation, questioning the school’s teachings when asking when, in life, will all that knowledge be used. Well, know that paying a little more attention in physics classes could help you be more successful in the kitchen, especially with the pressure cooker.
That’s because the much-feared instrument seems less frightening when you understand what’s going on there, between that tiny, noisy peg and the boiling water that surrounds your food.
The lawyer from Ceará Milena Gondim, 35, was not very familiar with the kitchen. As a gift from her grandmother, as soon as she decided to live alone, she got a shiny new pressure cooker.
One of the first times he went to put it on the stove, he almost turned the experience into an accident. “I went to try to make a dulce de leche and put the can with the label and everything. In addition, I left the pan on the fire for over an hour, waiting for the pin to beep,” he says.
The result was a dulce de leche stain on the roof of the apartment and a damaged pan. “The pot didn’t explode, but the can did. And the bottom turned black, without a drop of water. Despite everything, the candy was delicious.”
The possibility of producing the sweet at home, in fact, fascinates even experienced chefs. This is the case with Frenchman Erick Jacquin.
“One thing that surprises me a lot here in Brazil is that people make dulce de leche in the pressure cooker. They put condensed milk in the pan. I think it’s extraordinary, wonderful, it’s the best thing you do in the pressure cooker”, comments one of the judges of the MasterChef program.
Physics helps explain why the episode with Gondim had less of a candy face and more of a mischief face. Professor Douglas Gomes, master in Science and Mathematics teaching at the Federal University of Ceará, gives the idea.
“When you are going to cook a food, what cooks it? The water. So, what will make your food cooked is the water that will transfer thermal energy to it. The higher the temperature of the water, the faster will be the thermal energy transfer [o calor], and this transfer ends up being favored if you get this water above 100°C.”
The pressure cooker allows you to cook faster — and time, we know, has been increasingly valued. Jacquin, for example, ponders that it is a more common utility in homes, not so much in restaurant kitchens.
“Sometimes I use it at home, because in restaurants we have specific equipment. But it’s great to save time,” he says.
But, how does the pan achieve this speed in cooking? Because, mind you, it increases… the pressure (the obvious sometimes needs to be said). However, care must be taken that this pressure does not increase until it explodes, staging the fear of most amateur cooks.
To prevent that from happening, the main control valve is fitted — that pin that Gondim waited to beep.
“There comes a time when the pressure increases so much, reaching the limit of the pot, that this valve allows the steam to escape. With that, you can even lower the fire to save gas, as the water will also have reached the maximum temperature, reaching up to 120°C”, observes the professor.
In a country where cooking gas costs BRL 135 per cylinder, according to data from the National Petroleum Agency (ANP), everything is valid when it comes to saving — and the pressure cooker can also be a pocket ally.
Even after the incident, Milena Gondim was not defeated by the frustration of the first attempt, and today she continues using the pot presented by her grandmother.
“I started using it again and today I’m careful with cleaning. For someone with my profile, who lives alone and works a lot, it helps because it reduces cooking time a lot. And today I even make risotto in a pressure cooker”, he says.
The dulce de leche that flew to the lawyer’s kitchen ceiling only ended up there because the contents of the pan dried out. And this quickness of cooking, which made the water disappear, even has a formula in physics: pv = nRT It’s called the “Clapeyron equation”.
“With it, we understand that the increase in pressure makes boiling difficult, allowing the water to reach higher temperatures. In other words, the increase of particles in a gaseous state increases the pressure”, continues professor Gomes.
However, as the Enem period has passed and everyone is exhausted with calculations and formulas, there are more practical ways to understand how the pot works – so you can be careful and lose your fear.
The evolution of product design, for example, helps in this process of breaking free from trauma. Here, the old maxim that old pots make good food is a lie. In the case of pressure cookers, new technologies are the great allies for a safe and tasty cooking experience.
“Nowadays, it is common for an electric pressure cooker to have several different safety systems, to ensure maximum quality and reliability in use”, explains Philco’s portable line coordinator, Paulo Pelatti.
Among the electrical and mechanical systems of the brand’s cookware are, for example, the thermostat that turns on and off, keeping the temperature at safe standards, and the opening lock that prevents the lid from opening after the product has reached working pressure .
For this reason, cleaning all the valves on the pan is an essential part of kitchen safety. The practice is emphasized by chefs and teachers. “The maintenance of the pan must always be done with great care”, emphasizes Erick Jacquin.
“Never throw the hot pan under water and keep the valves very clean, they are the ones that guarantee protection”, complements Gomes.
When choosing, it is worth paying attention to the guarantee seals. “The best pressure cooker is the safest. It is important that the consumer read the descriptions attached to the products, check if it is certified by INMETRO and if it has the safety locks”, enumerates Monalise Couto, product designer for the Brinox brand.
“Generally, a traditional pressure cooker has four to five safety systems. In addition, having safety, any pressure cooker is suitable for anyone.”
With this care list up to date, you can have a smooth experience with the pressure cooker. Besides, when serving the dish, it’s even worth using a “dulce de leche a la Clapeyron” — after all, there’s no harm in the cook boasting that he even used the logic of physics in preparing a dessert.
I am currently a news writer for News Bulletin247 where I mostly cover sports news. I have always been interested in writing and it is something I am very passionate about. In my spare time, I enjoy reading and spending time with my family and friends.