Is the Pan Hot Yet?
Most home cooks do not properly preheat their skillets, which results in a lack of both crust and flavor development. This may be due in part to the advice of high-quality cookware manufacturers, who often suggest preheating a pan with a film of oil over low heat for only one to two minutes. Overheating, they warn, can cause discoloration. We followed their recommendations and were appalled at the sorry state of the food: pale, crustless, and with feeble browning. In our opinion, richly browned foods are worth risking discoloration (which, by the way, is easily removed with a little elbow grease).
How do you know when your skillet is properly preheated? The oil—smoking oil, to be exact—holds the answer. Measured into a cold skillet and heated for a few minutes, oil gives off wisps of smoke that serve as a visual alarm that the skillet is hot and ready. We tested our theory with beef steaks, chicken (skin-on), and fish fillets and steaks. In each case, oil that had just begun to smoke was a good indicator that the skillet was hot enough to produce well-crusted, good-tasting, and good-looking food without overcooking.
That said, not every kind of oil is suitable for high-heat browning and searing. Unrefined oils, such as extra-virgin olive oil, should not be used because their smoke points are low. Refined oils, such as vegetable, canola, corn, and peanut (be careful of the unrefined peanut oil carried in some grocery stores) work well because their smoke points are high (above 400 degrees). A word to the wise: Using just-smoking oil as a heat indicator is good only for browning and searing in very little oil, no more than a couple of tablespoons. Smoking oil is simply too hot for pan-frying and deep-frying.reprinted with permission from cooksillustrated.com