What is Sautéing?Sautéing is a form of dry-heat cooking that uses a very hot pan and a small amount of fat to cook the food very quickly. Like other dry-heat cooking methods, sautéing browns the food's surface as it cooks and develops complex flavors and aromas.
Sautéing Requires a Very Hot PanWhen sautéing, it's important to heat the pan for a minute, then add a small amount of fat and let the fat get hot as well, before adding the food to the pan. This hot fat helps to brown the surface of the food. Another key is to avoid overloading or overcrowding the pan.
Don't Overcrowd the PanIn order to achieve the desired browning of the food, the pan must stay hot throughout the cooking process. Too much food in the pan dissipates the heat, causing the food to steam or boil rather than sauté.
Keep the Food MovingThere's another element to sautéing — the toss. The word sauté actually means "jump" in French. Tossing or flipping the food in the pan ensures that it cooks evenly, but it also helps keep the pan hot.
How? Remember that when a hot thing meets a cooler thing, their temperatures eventually meet in the middle. The cooler thing grows warmer while the hot thing cools down.
Keep the the Pan HotTo illustrate, imagine a pan with green beans cooking in it. The beans at the bottom of the pan, closest to the heat source, are nice and hot, while the ones on top, where they're exposed to air, are cooler. And the longer they sit like this, the greater this disparity in temperature becomes.
So far, so good. However, you're eventually going to want to cook the beans on top, too. And once you flip them, the ones from the top come into contact with the pan's surface and, because they're cooler, they actually lower the temperature of the pan. This leads to the same problem mentioned earlier, where the food ends up steaming rather than sautéing. That's why we try to keep everything moving more or less constantly.
To facilitate this, some sauté pans have sloped sides, which makes it easier to flip those items in the pan without flipping them all over the kitchen. However, it's worth noting that this flipping or tossing technique is only really practical with smaller pieces of food, especially vegetables. So for steaks, larger cuts of poultry, fish fillets and so on, we're more likely to employ a technique known as pan-frying rather than sautéing — even if the dish is actually called sautéed fillet of sole or whatever. For a demonstration, here's a video on how to sauté vegetables.