Mac Lesggy explains how to make French fries less greasy thanks to science

Are you interested in less fatty potatoes? Science can help you with that. I wanted to come back to it this morning, because a few weeks ago I had the opportunity to meet Olivier Vitrac, at AgroParisTech. Olivier is a bit like the world-class specialist in French fries, and with him I learned so many things about frying that I wanted to share with you, in particular the secret Low fat french fries.

During frying, it is believed that oil gets into the potatoes, But not at all. Frying is immersing the food, as you like it, in a very hot and very dense medium, in this case oil or animal fat, for the purists, at 180 degrees. What will happen next? Three very specific phenomena.

so first, The oil imparts its heat by contact with the frying panThe temperature inside rises to 80 degrees, which is the cooking temperature for the starch, which is the primary ingredient of potatoes. At 80 degrees, gelatinous, the heart of the fry takes on that mashed-up consistency we all appreciate. The second phenomenon is related to the amount of water in potatoes, which is 75%. This water turns into steam that escapes from frying, these are the little bubbles we see in a frying bath. You will notice this water vapor escaping from the fry It prevents oil from entering it.

The last fact, on the surface of fry, which after a few minutes reaches a temperature of 180 degrees, takes place a whole complex of chemical reactions called Maillard reactions. This results in caramelization, which forms that thin, hard, and crunchy golden layer that is typical of fry. Which also prevents the penetration of oil into the fry. In fact as long as it’s in the pan, The oil is not suitable for frying.

Trim the surface of the fries

However, when removed, it is greasy. We have it on our fingers. What happens is that when it finds the surrounding air, the surface of the potato instantly cools. The water vapor that is still in the potato cells condenses below the surface. Water becomes liquid again, occupying a volume 1,700 times smaller than the initial water vapor. nature hates emptiness, This volume of steam Water is replaced by oil stuck to the surface of the larvae.

Obviously, the larvae suck out the oil. All this happens in a split second. Even if you filter the frying well on absorbent paper, it is too late, the oil has got into the frying pan, which is now important 10 to 12% of fat. To reduce this number, there is a way. Not in the process, because you just understood, the oil gets into the fryer when you take it out of the fryer It is an inevitable phenomenon. What we can do is reduce the surface area of ​​the caterpillars relative to their size.

In other words, if you go from a potato with a cross-section of half a centimeter to a potato with a cross-section of one centimeter, you increase the volume fourfold and the surface only twice as much. This makes for an even weight, half of the surface where the oil can penetrate for frying. So the fries will be less greasy. It’s a matter of engineering.