The main purpose of oil is not to prevent food from sticking. I had long thought this. Oil acts as a flexible conductor for heat and allows food to cook more evenly.
The smoke points of oil determine what they can be used for. Canola and corn have the highest smoke points and are ideal for frying. Butter and olive oil start to burn at lower temperatures and are more suited for other uses, such as flavor or body.
Removing sediment from used oil is crucial to maintaining (or restoring) a high smoke point. For the same reason, clarified butter has a higher smoke point than normal butter.
Always warm meat to room temperature before cooking – especially big cuts like steaks. A warmer steak will cook faster and thus taste jucier. Some people even put a steak in a warm oven before cooking.
A common myth is that searing meat seals in the juices. This is false. Heat drives water upward in the meat, where it will bubble to the surface and then escape. Flip just often enough to keep it moving back and forth, but not escape, and you will have juicy meat.
Always rest meat after cooking. Another myth is that this allows the juices to redistribute. While this happens to some degree, allowing the heat to even out and dissipate slightly will result in the fibers relaxing slightly, making them more tender. This is also the reason you should slightly undercook food so that it will be perfectly cooked after resting.
Always marinade in the fridge; never cook with used marinade as you should treat it as unsafe.
The secret to meat in chinese food is cornstarch.
An ice bath is the best way to stop cooking vegetables. You should do this when par-cooking to avoid yellowing or overcooking.
Boiling vegetables is a sure way to leach out all the nutrients. This is the basis of making soup; if you are actually trying to just cook vegetables, dial back the amount of water (or preferably, steam instead).
The proper way to hardboil an egg: place it in warm water, heat it to a rolling boil, and then TURN OFF THE HEAT. Wait ten minutes. The eggs will be perfectly cooked.
Fresh, healthy eggs have a very thick white and strong yolk. As eggs get older, the white gets runny and the membrane of the yolk thins out. The air pocket on the wide end also gets bigger from evaporating water.
There are two types of flour: bread flour and pastry flour. The difference is the amount of gluten that forms when you add water. The more you work dough, the more gluten will form. Gluten forms strong, starchy bonds in foods – think bread or bagels. A lack of gluten will give a more flaky texture – think pie crust or croissants (hence the term pastry flour).
All-purpose flour is just a compromise between bread flour and pastry flour that has a moderate gluten-forming capability.
Adding salt to boiling pasta helps it cook faster. In chemistry, the mechanism for this is boiling point elevation: more heat goes to cooking the pasta as opposed to evaporating the water. If you are on a sodium-restricted diet, do not add salt to boiling pasta.
The trick to perfect pasta is a rolling boil – it is the movement of the water that prevents it from sticking, not the absence or presence of salt.