How Rachel Roddy learned to stop worrying and love the pressure cooker | A kitchen in Rome

Until now, I’d hung on to an irrational childhood fear of the exploding pressure cooker, but I’ve recently rediscovered just how fast and efficient they are

This column ends well, with an ideal pan of beans, cooked in a third of the usual time, using less than a third of the usual energy. This column began decades ago, when I decided I was afraid of pressure cookers. Raking back though unreliable memories, it isn’t clear why, exactly, I was afraid. We didn’t have one at home, and relatives who did weren’t using them any more by the time we were growing up. There was no incident in the house next door, no scaremongering public-information film that had lodged itself in my mind. Unexplained fear became a quiet hang-up to which I clung even as pressure cookers evolved dramatically. Some of the best cooks I know told me to get over it.

Actually, this column began with a French physicist, Denis Papin. Born near Blois in 1647, he studied medicine before moving to Paris, where he assisted the Dutch physicist Christian Huygens in building vacuum pumps. Later, in England, Papin worked with the physicist Robert Boyle – whose pressure and volume of gas theory is known as Boyle’s Law – and built air pumps for the Royal Society of London. Papin’s research explored the relationship between boiling temperature and the surrounding pressure. When you cook in an ordinary pot at atmospheric pressure, water boils at 100C until it escapes as steam. Inside a sealed vessel, however, the trapped steam molecules move faster, increasing the surrounding pressure, which means the water boils at 121C. In 1679, Papin demonstrated a sensational invention: a closed vessel with a tight-fitting lid in which steam under pressure was used to cook food and soften bones; his “digesting engine”. One featurewas a small, weighted piston that moved up and released steam; a pressure-relief valve – and the original model for all modern pressure-cookers.

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