Do you know when you prepare the gnocchi and put them in boiling water? At a certain point you find yourself observing a rather curious phenomenon: the gnocchi begin to float! It seems incredible, but generally when we cook the gnocchi it is as if we had a “natural timer“That warns us of their cooking when we see them emerge on the surface. But have you ever wondered why this behavior is in a phenomenon called amateur gelatinization. When the gnocchi cook, the starch contained in the potato, or in other ingredients such as flour and semolina, begins to absorb water and swell. This process increases the volume of the gnocco, making it so larger e less densetherefore, for Archimedes’ law, just like a ping-pong ball in a glass of water, start floating.
The gelatinization of starch makes the gnocchi less dense
What exactly is gelatinization? It is a chemical process which takes place when we heat the starch in the presence of water, starting from temperatures between 60-80 ° C. During cooking, starch granules swell, absorb water and their internal organization is modified: from a semicroristalline and orderly structure of the starch molecules you move on to one wider and more disordered structureleading to a softer consistency and a lower density of the gnocco once cooked.
It is as if the water, entering the structure of the starch, actively contributed to the cooking of the dumpling, acting as “softener“And making it more soft and tasty to our palates. The gelatinization of starch is a very recurring phenomenon in the kitchen: also the Bread cookingwhen we mix water and flour and then bake, provides a phenomenon of gelatinization that contributes to making bread soft when we churn out it.
This phenomenon is irreversible: Once the starch has been gelatinized, it cannot return to its original state. Also, if we decided not to drain the gnocchi but to let them cook more time, we would observe one progressive degradation Of the starch grains, with increasingly consistent gnocchi due to the slow release of Amilosio, the fundamental component of the starch which, together with the amylopectin, gives the rigid structure of the sock that is not yet cooked.
So when we cook the gnocchi, we are not only boiling some potato balls; We are witnessing a real structural change which transforms the starch into a gelatin that softens and determines the cooking of the gnocchi perfectly. The starch will no longer be rigid as before, but it becomes a sort of gel that holds the humidityallowing the gnocchi to cook uniformly and remain soft. In a nutshell, without the gelatinization of starch, the gnocchi would not be so light, soft and tasty! Also, thanks to this phenomenon, We can avoid timing the cooking minutes: Just observe this nice floating which, almost as for kindness, warns us of cooking.
Archimedes’ law: because they float
The reason why the gnocchi floats once their density decreases is linked to the Archimedes lawthe same scientist of the famous exclamation “Eureka!”. This law, one of the pillars of classical physics, states that a body immersed in a fluid, such as water, receives a push upwards equal to the weight of the fluid that moves. Put simply, If the density of the object is lower than that of the fluid, the object floats. The ping-pong ball contains air inside: if we immerse it in the water and push deeply, the push of Archimedes will bring it back to the surface, precisely because it is a less dense object of the water. Conversely, a stone sinks because its internal structure gives it a much higher density than that of the water, therefore we will never see it to emerge on the surface.
In the case of the gnocchi the starch absorbs water during cooking, swelling, increasing its size and reducing the density of the dough. Since the density of the gnocchi becomes lower than that of the water, they tend to go up to the surface.
The next time you cook this dish, remember to thank the science that also puts its signature in common actions such as the preparation of gnocchi to ragù.
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