How do you mix cheese and hot water without making it lumpy? This is the question for anyone who has ever tried to make the popular dish cacio e pepe, which consists of pasta, the Italian hard cheese pecorino and pepper.
Physicists have now taken on the challenge of solving this culinary puzzle and sharing it with pasta enthusiasts around the world.
In the journal Physics of Fluids, scientists from the Max Planck Institute for the Physics of Complex Systems in Dresden, the University of Padua and other institutions report their findings – and provide what they consider to be a “foolproof recipe”.
Normally, fatty substances like cheese do not mix well with water, which is why starch is an important binding agent. Through tests, the research team discovered that two to three per cent of starch relative to the amount of cheese is optimal for a creamy, uniform sauce.
Pecorino is a hard cheese made from sheep’s milk that is made in various regions of Italy. Photo: Shutterstock
Lower than 1 per cent and the risk of lumps is too high, while more than 4 per cent makes the sauce stiff and unappetising.
Heat is also crucial: the sauce cannot tolerate much of it. Excessive temperatures destroy the proteins in the cheese, causing it to form lumps – a process the researchers refer to as the undesirable “mozzarella phase”.