Molecular weight. Conduction. Evaporation. And how water is so important to cooking.
1-Minute NomNom
You could say water loves cooking. Or cooking loves water. Either way, water plays a very important and interesting role whenever we cook food because it is a small molecule and has a small molecular weight.
One way food is cooked is by conduction. Conduction occurs when the surface of food, e.g. a piece of meat, is heated and becomes hotter than the rest of the food. The heat energy causes the molecules at the surface to move more rapidly than the molecules in the colder regions.
When the former molecules bump into the latter, the latter begin to vibrate quickly too, and the heat energy is transferred (hence the phrase “heat transfer”). The process continues until the center is heated and all parts of the food are cooked.
In a piece of meat, for example, each water molecule is smaller and lighter than a fat or protein molecule. The heat energy thus causes the water molecules to move the most rapidly, and, as a result, they conduct and transfer the most heat needed to cook our food.
At the same time, again because they are small and light, water molecules at the surface could gain enough energy to escape from the surface as evaporation. If this is allowed to happen for too long, such as when a piece of meat is left to cook for a really long time, the surface can become very dry (find out why recipes ask you to blot water off raw meats in the 1-Minute NomNom “Water you mean you like me a blot?”). A dry exterior is not very yummy, unless of course we intentionally want it to be dry such as in deep fried foods.
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photos: in order – deposit photos/HHLtDave5; tolokonov; mantonino
