Physics helps us understand how to cook spaghetti al dente

Whether they are oriental noodles or spaghetti with garlic and oil, cooking pasta is serious business: in fact, a couple of more minutes of cooking are enough to ruin an entire recipe. Scientists at the University of Illinois, in the United States, are also well aware of this.In a study published in the journal Physics of fluids, they investigated the physical and mechanical processes according to which pasta swells, softens and finally becomes sticky while it absorbs boiling water, also finding that, for the same size, the amount of salt added to the water has a great influence on cooking times. From these data they have developed a quantitative method that promises to obtain perfect pasta al dente every time.

Science and cuisine Cooking has a lot to do with science: not only because of the consistency, cooking and flavors of food they are governed by the laws of chemistry and physics, but also because most of the time, just like in the laboratory, one proceeds by trial and error. Then there are executions that require several attempts to get a good result: for example, obtaining the perfect pasta al dente, whose cooking times often vary depending on the format and the recipe to be followed. But is it possible to develop a "scientific" method to find the precise cooking times of pasta? As reported in a press release, researchers at the US university, who usually study the physical characteristics of very flexible and deformable elastic fibers, asked this question during the Covid-19 pandemic, working on it at home and in the laboratory.

"In recent years, we have joked about how the forces that regulate paste adhesion are very much related to our work," said Sameh Tawfick, lead author of the study. "We therefore realized that, in particular, the mechanical consistency of spaghetti changes as a function of cooking and our analysis can demonstrate a relationship between adhesion, mechanical consistency and cooking".

Physics and pasta al tooth The objective of the physicists was to investigate the swelling and softening process of pasta, in particular spaghetti, due to the imbibition (absorption in the absence of chemical reactions) of liquids: during cooking, in fact, as the water penetrates inside, the dough gradually softens, while the starch of which it is composed swells and relaxes. This is associated with changes in its internal structure, with deformation and adhesion processes between the pasta itself, or the phenomenon whereby, lifting a forkful of spaghetti from boiling water, the more overcooked they are, the more they adhere to each other. In fact, when the pasta is extracted from the water, the surface tension exerts a force that causes the spaghetti to stick to each other.

In particular, the researchers measured various parameters, such as expansion of the shape, rigidity of the structure and water content of spaghetti cooked for different time intervals. The data obtained was then used to build a theoretical model that explained the dynamics of water swelling of starch-based materials. After that they took the pasta from boiling water and let one spaghetti cool next to the other, measuring the portion that adhered to the others with a ruler. The researchers found that this measure was directly correlated with the cooking times of the pasta.

Help for home cooking There's more: the times calculated in this way varied considerably not only according to the spaghetti format, but also to the addition of salt to the water. And this has greatly affected the scholars. For the future, the team, in addition to continuing to investigate the role of salt in these processes, hopes the study will help find simple methods for studying soft and elastic materials. In addition, the authors hope, for the method they have devised, a future in home cooking: in fact, they write in the study, measuring spaghetti with a ruler rather than tasting its consistency, however bizarre, it would be optimal to always obtain a pasta al tooth.

"Perhaps - reads the article - this experiment can be further validated by professional chefs and one day used by home cooks".