why does one need to preheat the oven before baking?

Answer 1

You are basically using heat to bring about a physical and chemical reaction. Different temperatures held for different time periods bring about different changes. That's why recipes need to specify the oven temperature and the length of baking time. If you don't follow those instructions you may get a different result (e.g. dry or soupy), or some of your ingredients may fail to cook (e.g. uncooked meat) or make their contribution (e.g. not rise).

Preheating your oven assures that your item is exposed to the correct temperature; your timer will assure that it was there for the correct amount of time. The rest is finesse and intuition.

Bake some cookies if you want to test this all out.

Answer 2

Preheating depends on lots of things, like the type of oven you have (gas? electric?), the age of the appliance (older ones will take longer), the ambient temperature in your house, etc. And no, your oven will NOT become too hot if you leave it on for too long, assuming your oven is working properly; there's a thermostat that shuts it down when it reaches the target temperature. It will, however, make your kitchen warm, the longer you leave it on. If you are baking...bread, cake, cookies, basically anything that contains flour...preheating is a necessity, not just a recommendation. Any oven has some indicator that the temperature has been reached, like a light or a "click". For baking, wait until you see that light (or hear that click), and THEN let the oven heat for an additonal 10-15 minutes. Just because the thermometer inside the oven registers 375 degrees (or whatever), it doesn't mean that the heat has permeated the whole oven yet. When baking, the idea is to have a constant, steady temperature, so it's best to let the oven build up residual heat. That's also why you shouldn't open the oven door and "peek" at the food while it's cooking.

Answer 3

You don't necessarily. One of my cook books rants about the waste of power and time caused by preheating. But for some things, it does matter. For example, if you are putting a roast in at 475 and then turning it down to 350 after a minute or two, well that obviously wont work if you don't preheat.

Things that are delicate, and have short baking times, might come out wrong also if you don't preheat.

But for most foods that are slow cooking in an oven, it really doesn't matter if you skip the preheat.

Answer 4

It depends on what you cook. FOr cakes and such, the steady heat is needed to produce the product according to the receipe. One cannot predict the rate of heating of an oven (some are 10 minutes, some are less) and the cooking time would differ.

For meats, like a turkey or ham or roast...no preheating is needed. The time varties for meat too widely and an internal temperature is a better gauge of doneness. Therefore, put it in and turn it on.

Answer 5

it helps get the oven nice and hot before u bake anything.

Answer 6

Helps to time the correct cooking time