To begin with, not all pans burn. Teflon-coated or non-stick pans do not have this problem. Cast iron pans do not burn, either, provided they are made properly.
But for stainless steel pans, food sticks very well. Let’s find out why.
What makes things stick
You’ve probably noticed that nothing sticks to a cold pan. So you have to look toward high temperature. You probably remember from your high school chemistry class that some chemical reactions go faster when the temperature is raised. And some reactions don’t go at all at low temperatures. Hundreds of chemical reactions take place during cooking – some substances turn into other substances at the molecular level.
It’s also worth remembering why some objects are easier to break than others. The fact is that when we break an object, we break the bond between the molecules of matter. In order to break the bond between specific atoms or molecules, it is necessary to apply a force that is higher than the energy that binds those atoms or molecules together. The higher this bonding energy, the harder it is to break an object. For example, a brick has more chemical bond strength than an apple. Liquid water, on the other hand, has very little bonding energy, but it’s still there. That’s why water collects in droplets – neighboring water molecules form a bond. Even the seemingly chaotic moving atoms of gases have an almost imperceptible bond.
Energy is needed both to break the bond and to form it. In our case, the energy to form a bond comes from the fire heating the frying pan.
When a frying pan is heated, strong bonds form between its surface and the surface of the food. You may have noticed that protein foods like fish and meat burn the best. The fact is that the amino acids that make up proteins have a molecular structure that bonds well with the iron atoms on the surface of the pan. Both the iron atoms and the amino acid molecules have a polar structure-they are like a magnet-they have a “plus” on one side and a “minus” on the other. The “plus” of the amino acids is magnetized to the “minus” of the iron atoms, thus forming a strong bond.
How to make things not stick
To prevent this from happening, there must be a layer between the two polar surfaces – the pan and the meat. And this layer must itself be non-polar. Because if it is polar, then it will react on its own. And exactly the same bond is formed, only with the participation of the layer.
Oils, for example, have such properties. They are all non-polar solvents. That’s why food is fried in oil at home. It is important that the oil should cover the entire surface of the contact area between the pan and the meat. Because it is in the areas of direct contact will be formed sticky. It is also worth remembering that oil, like other liquids, can evaporate. So it is necessary to make sure that there is enough of it.
Unique properties of Teflon
Another known material that prevents metal contact with food is Teflon. It is one of the most inert (from Latin inertia – rest, constancy, invariability) substances in the world. That is, Teflon can not react with almost any substances. Even very aggressive ones like aqua regia (a mixture of nitric and hydrochloric acids, which can dissolve almost anything). Moreover, this feature of Teflon is preserved at sufficiently high temperatures – up to 260 º C. But to heat an ordinary frying pan on the stove to such temperatures is difficult because the pan is not only heated, but also cools, giving part of the heat to the environment. And it is unlikely to cook anything at this temperature – the food is likely to turn to charcoal by then.
The fact that Teflon is inert is not only good in terms of cooking, but also in case the coating of the pan gets damaged. If a piece of Teflon enters our body – it will not react with anything and inside the body, and therefore can not harm it, and leaves us in the same form as entered.
How Teflon can be dangerous
Perfluorooctanoic acid is used in the production of Teflon. It is a carcinogen and a toxin (poison). Normally, it has to be broken down during production. It breaks down into non-toxic elements at 300°C, and one of the production steps is heating to 420°C. This is strictly controlled and the finished pan should not contain this harmful acid. Some manufacturers don’t use it in production at all. But if you buy a frying pan from some unknown manufacturer, you should be aware of this danger.
For example, there are no regulatory documents in Russia that limit industrial contamination of Teflon, including perfluorooctanoic acid.
So if you’re thinking of using teflon cookware, buy it from trusted manufacturers and don’t overheat it.
Still, when using a Teflon frying pan, it is better to use oil at least in minimal amounts. The decomposition temperature of oil with smoke emission is 200 ºC, which is a good indicator that you should turn down the fire.
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