What’s better, especially for us in the Bel Paese, than to eat a good dish of pasta? It is a healthy, healthy and decidedly appetizing meal for us Italians. And what a hunger! When the water boils we are ready to drop our pasta, whether it is as long as spaghetti or short like the pens, but … if the flame is high and we distract each other here is trabocca a little water mixed with a curious one white foam. But why does this phenomenon occur? The cause is precisely thestarch contained in the pastawhich is gradually released during cooking and behaves like a small “foam architect”. Starch increases the viscosity of the liquidstabilizes the steam bubbles by creating a real “Viscose network” which then flows into that characteristic foam. Nothing mysterious, only a normal chemical-physical effect due to the very nature of the pasta.
The white foam of the pasta during cooking is caused by starch
The pasta is mainly made of starch, i.e. long sugar chains (carbohydrates) enclosed in tiny granules. When we throw the pasta into boiling water, these granules swell, break and slowly begin to free starch molecules. These have an important property: they retain a lot of water and make the liquid more dense and viscous. In practice, cooking water becomes less and less similar to simple water and increasingly similar to a “cream”, which in technical jargon is defined colloidal solutionan heterogeneous solution, in which particles of a substance (in our case the starch), are finely dispersed in a solution, that is, the cooking water of the pasta. Not surprisingly, the chefs recommend keeping aside a ladle of this water rich in starch to stir the pasta or risotto: it acts as a real “Collante” For condiments, linking them to each other and generating a real creaminess added to the dishes. In the preparation of carbonara pasta, for example, the cooking water containing starch is essential to give the right body to the so -called “carbocrema”.
Pasta starch creates bubbles that do not burst
In a pot of boiling water, the steam bubbles arrive on the surface and burst immediately, simple. But if there is starch in solution, things change! The starch molecules surround the bubbles e they strengthen the wallsjust as the soap surfacts do when we wash and formed a lot of foam. Thus the bubbles become more stableaccumulate and do not explode immediately. The result is one thick foam which covers the surface of the pot. It is a bit like when the cappuccino is made: the milk foam remains compact because proteins and sugars stabilize the air bubbles. Something similar happens in the pasta, only that instead of milk proteins there are the stars of flour.
How to prevent the bubble water from getting out of the pot and because it overflows
There starch foam It is not just a curious phenomenon: it is precisely the reason why the pot is sometimes trabocca. When the bubbles accumulate on the surface, they form one layer often which hinders the normal escape leakage. The boil becomes “agitated”, the foam grows with heat and in the end it exceeds the edges.
In a nutshell, the amount of foam depends on two practical factors:
- The water/pasta ratio: the less water is, the higher the concentration of starch and the more foam is produced;
- the intensity of the fire: a flame too high in a short time produces many bubbles, which immediately find the support of the starch network.
That’s why often The small and filled pots are the first to overflow. Obviously, we are not talking about something toxic or harmful … On the other hand, then we eat it! It is the same substance that makes dishes such as carbonara or particular risotto. The trick lies in checking it. To avoid disasters in the kitchen, small tricks are enough: to use larger pots, mix from time to time to break the surface layer, or slightly lower the flame When the water starts to boil. The next time our Rigatoni pot will be about to overflow, we can smile: it is nothing serious, it is only the starch chemistry in action.
