I r(ul)efuse

Because in a recipe it's impossible to specify cooking times without pre-heating. It's easy to say 10 minutes at 200 degrees, because this would be exactly the same for everyone. Every oven is different, so the time would be different depending on your oven, which the person writing the recipe can't know. So if the instructions on something like bread say pre-heat and bake for 10 minutes at 200 degrees, they know the result would be good.

There is also the fact ovens warm up differently. If there is a heating element within the compartment where the food is being heated (especially above), this element gets way too hot and emits a lot of infrared radiation whilst heating up the oven. It does this because it wants to get to the set temperature as fast as possible. Once it gets there it only needs to maintain that temperature, which is much easier, so the heating element gets much less hot during this time. If you set something like a cake in the oven with a heating element right above it, best case the top of the cake gets baked more than the rest, worst case the top gets burnt before the inside cooks.

Then there's the fact whilst heating the temperatures inside the oven fluctuate a lot, some parts get hot fast, other parts take more time. When you have food that's sensitive to that you def need to preheat.

And there's a lot of chemistry going on, for example some foods get really greasy if they don't get hot enough while cooking. Whilst these food could be cooked with the temperature going from 50 - 150 degrees, the end result would be much better if it's just cooked at 200 during the whole process.

Now there are a lot of cases where this doesn't matter and if you know your oven well enough you can compensate. But there are plenty of legit reasons to pre-heat and you may even have better results when pre-heating, even if the end result was fine before.

So I agree, people should pre-heat and there are tangible benefits!

As a preheated oven, I can confirm this

The oven is quite cool on the other hand

I actually cook a lot and I do this. The benefits aren't very significant but it certainly doesn't ruin meals (if you cook like me lol).

It's more energy efficient and doesn't affect the food as much as you would think. Because of the temperature difference between your oven and house, and that heat rises, tons of heat flies out of the oven as soon as you open it. That is why there's the massive blast of heat from the oven when you open it, it's practically flying out at mach speed.

Afterwards there are only minor benefits from preheating the oven because the temperature has dropped significantly and it has preheated itself (and food) again anyways.

Secondly I never strictly use timers to tell me whether my food is cooked or not. Even "30 mins at 300 degrees" on different ovens will give you varied results, because built in oven thermometers are not very accurate. Additionally to make the oven look more accurate the screen will lie to you. On my oven, quickly after reaching temp, it may say "400". If I turn my oven off and on, and immediately set it to 400 again it'll say something like "325", because it's a lying sack of shit that tries to trick me into thinking it's faster and more accurate than it really is.

That's why independent oven thermometers are so popular. This is also why I gauge my food by it being cooked or not. I look at the crispyness and browning of the food. If it's a good color, I remove it. If undercooked, no shame in returning it to the oven. If the outside is burnt and the inside undercooked then that's the fault of either the recipe, cooking vessel or temperature (which is part of the recipe anyways).

Thirdly it makes managing things marginally easier. Instead of trying to optimally time your preheat as to not waste time, but also not to waste energy for 20 minutes, it's easier just to turn it on with the food in.

I hope you understand why I don't believe in the satanic oven preheating conspiracy.

And overcook at the same time.

This is such a tiny hill to stand on, and I love it.

:3

You must know Josh.

either you are messing up your final product unknowingly or realizing it's undercooked and having to leave it in the oven for longer to make up the difference.

For frozen pizza/nuggets/etc, the cooking time is always a range. I always just put it in while it preheats and set the timer for the top of the range. Everyone's oven and preferences are different anyway so it's not like some exact science. If they're underdone, I leave them in another minute. Overall it saves time.

It's almost always never as good just microwaved, if I'm really in a hurry I'll do a half half and heat it in the microwave and finish off in the oven

Leavened products, especially chemically leavened ones like cakes, need the oven to be hot when they go in for proper texture. The heat creates steam which means more and bigger bubbles, and the baking powder also reacts better at high temperatures, producing even more bubbles. And these bubbles need to start growing before the protein in the flour starts to set, otherwise they stay small and you get a dense texture.

I don't care what you say. I stir-fry in a cold pan like a boss. I like my vegetables flopsy and oily thank you very much

It really depends on what you're doing. Consider a steak: If you put it into a cold pan and heat it up it's going to be 110% done on the inside before you get to temperatures that cause browning -- the protein is going to denature at ~70C, Maillard reactions occur at about 140-160C. So rule of thumb is if you want crisp or brown anything, you probably should blast it with some actual heat.

Then, when it comes to printed recipes: While every oven bakes differently they heat up even more differently, so if you want to give a baking time including the pre-heat is going to increase the error bar quite a lot.

And then there's stuff that needs proper rituals to turn out good, bread is probably the best example: Preheat, steam, falling temperature. Sure you'll get something edible if you put some dough in a cold oven but it's not going to be nearly as good, raise strangely, have structural issues, and forget about having a proper crust.

Oh, coming back to pans: "Hot pan, cold oil", as the Chinese say, is how you make iron pans non-stick: Without preheat not only is your steak going to be soggy, it's also going to be glued to the pan. If you use a teflon pan at the temperatures needed for a proper sear you'll quickly need to buy a new one while even bargain-bin iron pans are going to last generations.

I think I got that to work correctly once 😮‍💨 like baking a pizza went poorly but baking a chicken works I think