09-05-2025
Italian physicists explain how to avoid lumps in cheesy pasta sauce
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 Italian pasta 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 complex 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 provided 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 2-3% starch relative to the amount of cheese is optimal for a creamy, uniform sauce.
With less than 1%, the risk of lumps is too high, while more than 4% makes the sauce stiff and unappetising.
Heat is also crucial, as 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."
That's why the water should be cooled slightly before mixed it with the cheese, the scientists say.
"A true Italian grandmother or a skilled home chef from Rome would never need a scientific recipe for cacio e pepe," the study states. "For everyone else, this guide offers a practical way to master the dish."
For those attempting the recipe, the researchers recommend preparing a starch solution – ideally with potato or corn starch – rather than relying on pasta water, where the starch content is unknown.
Dissolve four grams of starch in 40 grams of water and heat it until it reaches a gel-like consistency. To this gel, add another 80 grams of water to cool the mixture.
Only then should the Pecorino (160 grams in this example) be stirred into the starch solution until a homogeneous consistency is achieved. Finally, warm the sauce to serving temperature. Add pepper, mix in the pasta, and the dish is ready.
The researchers had not only scientific curiosity but also a personal interest in the project. "We are Italians living abroad. We often have dinner together and enjoy traditional cooking," co-author Ivan Di Terlizzi from the Max Planck Institute in Dresden is quoted as saying in a statement by the American Institute of Physics.
Cacio e Pepe, he said, seemed like an interesting dish from a physics perspective. "And of course, there was the practical aim to avoid wasting good pecorino."
