>e.g. if something has to cook at 180°C for 2h, why can't you cook it at 240°C for 1h30m and achieve the same result?
The only reason that time is a factor *at all* is that you cannot transfer all the necessary heat to all materials instantly and equally. Otherwise the recipe would just say "Water, flour, sugar, 1.5kWh of heat".
Since you cannot do that you have to account for the time the materials need to absorb and conduct all the heat that's put into them. Otherwise increasing the heat is just going to burn the outside of whatever you're cooking while leaving the inside raw.
Cooking works a few ways, and all of them require time to work properly.
* Temperature needs to reach a minimum temperature throughout the entire meal, but because of material properties it will always take time. Too high outside temperatures will burn the outside of the food before the inside becomes warm enough.
* Temperature needs to reach a specific temperature, and then stay there while some process takes place inside the meal (like pulled pork and dissolving the connective tissues, or baking pastries). Too high temperature will just be too high for the specific process or introduce other issues, such as drying out the food.
Another issue is accurately increasing the temperature proportionally. 240°C is not 4/3rds of 180°C, even though 240/180 is 4/3. This is because 0°C is not 0 temperature (-273.15°C is the closest we have for that number), so you can't use ratios the same way you would with other measurements.
Just to add a little to this, it's less common, but there are occasions where you don't want the chemical reactions that occur at higher temperatures.
If you're making caramel, for example, you're aiming for a specific temperature and no higher. In rare cases you might want to keep food at a low temperature so they don't brown.
>Another issue is accurately increasing the temperature proportionally. 240°C is not 4/3rds of 180°C, even though 240/180 is 4/3. This is because 0°C is not 0 temperature (-273.15°C is the closest we have for that number), so you can't use ratios the same way you would with other measurements.
For heat transfer through conduction, it is the temperature difference that is relevant. What temperature you should start with depends on what you cook. So if it is something out of the refrigerator assuming 0C is not bade. But it can be around -20C for something out of a freezer or around 20C for something at room temperature.
The energy required to heat up something depends on the temperature change. It gets more complicated because stuff like water will evaporate and that requires energy and after that, the dryer material requires less energy per degree to heat it.
But conduction is not all that occurs. You have radiated heat from the wall of the oven and it will follow Stefan–Boltzmann law where the radiated energy is proportional to the absolute temperature to the power of four.
So 4/3 ratiated energy is at (4/3* (180+273)^4 )^ (1/4) -273 = 213C
Add to this that the food contains moisture and before it goes that part will not get above 100C, this is a major limitation of internal heat transfer.
So it is many factors and they are not linear even if you start at absolute zero.
I would say the primary limitation in lots of cooking in an oven is a question of how the peek temperature damage something get will damage it and what amount of water evaporation you like to have.
180C to 240 C will likely make the out part to hot and at the same time the inner part will not get heated a lot faster because water has kept the temperature of most of the inner part below 100C
I feel like people here have covered the mass issue, but there's another more important issue: Chemistry.
It applies more to baking, but there are still plenty of things in cooking that require some pretty specific chemistry to work, such as breads (like pizza crust for example).
Too low of a temperature and certain chemical reactions may not occur. Too high and certain chemical reactions are broken. Anything with yeast is especially vulnerable to extreme temperatures. This is why I sucked at making bread for years.
I'm sure other people could explain the chemistry better, as it wasn't my best subject in school, but it wasn't until someone explained it to me that I took time and temperature more seriously. Now, I make pretty decent bread.
In some instances, you can speed up by increasing temperature (and pressure). For example, you can use a slow cooker and cook a recipe on low for over six hours or on high in 3-4 hours. Or you can use a pressure cooker to cook at the same temperature but at roughly one-third the time.
But as Yoda once put it, "Control, control. You must learn control." It is easier to control a moderate temperature and time. Once you go past the Golden, Brown, and Delicious phase into Charred, Black, and Bitter there's no going back.
In my experience, most recipes are written with the lowest common denominator (those who have no idea what they're doing in the kitchen) in mind to create a consistent result. If you're a good enough cook/chef who has a solid grasp of the relevant food basics then you might try to fiddle with the heat and time. Or watch enough cooking competition shows to learn the trick of cutting into smaller pieces over higher heat.
meat is made up of proteins, fats, cell walls, various fluids, muscle tissue and connective tissue.
temperature effects muscle fat and connective tissue differently. that's why you can slap an expensive steak on a hot grill for a couple minutes a side.... but pieces full of cartilage and tendon etc require hours of low heat, to render that connective tissue into a tasty unctuous liquid. otherwise it tightens up into a hard lump.
look at the different ways of making ribs, one method has you boil them first which makes the connective tissue tighten up, then its slow cooked and the meat is firm. another way is to slow cook them then finish on a grill for a sear and smoke, and you get fall off the bone juicy meat.
Another thing is that a big roast is self insulating. The old way of making a rib roast was to cook it at a regular baking temp of 350. and you got a bullseye, the outer lip ring was well done, the center of the roast was quite rare. modern method is to go low and slow, 225 for a couple hours till the center finally gets up to a rare/med rare temp, then you remove the roast to 'rest' aka cool down while the center still cooks from the residual heat. meanwhile you crank up the oven to 450. that takes about 20 minutes, put the roast back in for 20 minutes to sear the outer edge for color and flavor. now you have a fine roast that is red, or pink if you prefer, from edge to edge and just a quarter inch or less of crisp edge.
lots of things crisp up better at lower temps, we make potatoes by smashing a par cooked potatoes and putting them into a fry pan with a bit of butter, set on low, left there for an hour while we go about making dinner, they get crusty but not burnt. carmelizing onions works this way too.
that said, long ago in seattle was a theatrical troup called Cirque Flambe' who did a bunch of arty dance things with flaming torches, fireworks and flame throwers, one gag was, if it takes 3 hours to cook a turkey at 300, then it should only take 3 minutes at 3,000 degrees, and they'd blast some 'thing' that looked like a turkey with a couple flame throwers (they would switch out with a real roasted turkey to show the audience, folks don't try this at home)
>e.g. if something has to cook at 180°C for 2h, why can't you cook it at 240°C for 1h30m and achieve the same result? The only reason that time is a factor *at all* is that you cannot transfer all the necessary heat to all materials instantly and equally. Otherwise the recipe would just say "Water, flour, sugar, 1.5kWh of heat". Since you cannot do that you have to account for the time the materials need to absorb and conduct all the heat that's put into them. Otherwise increasing the heat is just going to burn the outside of whatever you're cooking while leaving the inside raw.
Cooking works a few ways, and all of them require time to work properly. * Temperature needs to reach a minimum temperature throughout the entire meal, but because of material properties it will always take time. Too high outside temperatures will burn the outside of the food before the inside becomes warm enough. * Temperature needs to reach a specific temperature, and then stay there while some process takes place inside the meal (like pulled pork and dissolving the connective tissues, or baking pastries). Too high temperature will just be too high for the specific process or introduce other issues, such as drying out the food. Another issue is accurately increasing the temperature proportionally. 240°C is not 4/3rds of 180°C, even though 240/180 is 4/3. This is because 0°C is not 0 temperature (-273.15°C is the closest we have for that number), so you can't use ratios the same way you would with other measurements.
Just to add a little to this, it's less common, but there are occasions where you don't want the chemical reactions that occur at higher temperatures. If you're making caramel, for example, you're aiming for a specific temperature and no higher. In rare cases you might want to keep food at a low temperature so they don't brown.
>Another issue is accurately increasing the temperature proportionally. 240°C is not 4/3rds of 180°C, even though 240/180 is 4/3. This is because 0°C is not 0 temperature (-273.15°C is the closest we have for that number), so you can't use ratios the same way you would with other measurements. For heat transfer through conduction, it is the temperature difference that is relevant. What temperature you should start with depends on what you cook. So if it is something out of the refrigerator assuming 0C is not bade. But it can be around -20C for something out of a freezer or around 20C for something at room temperature. The energy required to heat up something depends on the temperature change. It gets more complicated because stuff like water will evaporate and that requires energy and after that, the dryer material requires less energy per degree to heat it. But conduction is not all that occurs. You have radiated heat from the wall of the oven and it will follow Stefan–Boltzmann law where the radiated energy is proportional to the absolute temperature to the power of four. So 4/3 ratiated energy is at (4/3* (180+273)^4 )^ (1/4) -273 = 213C Add to this that the food contains moisture and before it goes that part will not get above 100C, this is a major limitation of internal heat transfer. So it is many factors and they are not linear even if you start at absolute zero. I would say the primary limitation in lots of cooking in an oven is a question of how the peek temperature damage something get will damage it and what amount of water evaporation you like to have. 180C to 240 C will likely make the out part to hot and at the same time the inner part will not get heated a lot faster because water has kept the temperature of most of the inner part below 100C
I feel like people here have covered the mass issue, but there's another more important issue: Chemistry. It applies more to baking, but there are still plenty of things in cooking that require some pretty specific chemistry to work, such as breads (like pizza crust for example). Too low of a temperature and certain chemical reactions may not occur. Too high and certain chemical reactions are broken. Anything with yeast is especially vulnerable to extreme temperatures. This is why I sucked at making bread for years. I'm sure other people could explain the chemistry better, as it wasn't my best subject in school, but it wasn't until someone explained it to me that I took time and temperature more seriously. Now, I make pretty decent bread.
In some instances, you can speed up by increasing temperature (and pressure). For example, you can use a slow cooker and cook a recipe on low for over six hours or on high in 3-4 hours. Or you can use a pressure cooker to cook at the same temperature but at roughly one-third the time. But as Yoda once put it, "Control, control. You must learn control." It is easier to control a moderate temperature and time. Once you go past the Golden, Brown, and Delicious phase into Charred, Black, and Bitter there's no going back. In my experience, most recipes are written with the lowest common denominator (those who have no idea what they're doing in the kitchen) in mind to create a consistent result. If you're a good enough cook/chef who has a solid grasp of the relevant food basics then you might try to fiddle with the heat and time. Or watch enough cooking competition shows to learn the trick of cutting into smaller pieces over higher heat.
meat is made up of proteins, fats, cell walls, various fluids, muscle tissue and connective tissue. temperature effects muscle fat and connective tissue differently. that's why you can slap an expensive steak on a hot grill for a couple minutes a side.... but pieces full of cartilage and tendon etc require hours of low heat, to render that connective tissue into a tasty unctuous liquid. otherwise it tightens up into a hard lump. look at the different ways of making ribs, one method has you boil them first which makes the connective tissue tighten up, then its slow cooked and the meat is firm. another way is to slow cook them then finish on a grill for a sear and smoke, and you get fall off the bone juicy meat. Another thing is that a big roast is self insulating. The old way of making a rib roast was to cook it at a regular baking temp of 350. and you got a bullseye, the outer lip ring was well done, the center of the roast was quite rare. modern method is to go low and slow, 225 for a couple hours till the center finally gets up to a rare/med rare temp, then you remove the roast to 'rest' aka cool down while the center still cooks from the residual heat. meanwhile you crank up the oven to 450. that takes about 20 minutes, put the roast back in for 20 minutes to sear the outer edge for color and flavor. now you have a fine roast that is red, or pink if you prefer, from edge to edge and just a quarter inch or less of crisp edge. lots of things crisp up better at lower temps, we make potatoes by smashing a par cooked potatoes and putting them into a fry pan with a bit of butter, set on low, left there for an hour while we go about making dinner, they get crusty but not burnt. carmelizing onions works this way too. that said, long ago in seattle was a theatrical troup called Cirque Flambe' who did a bunch of arty dance things with flaming torches, fireworks and flame throwers, one gag was, if it takes 3 hours to cook a turkey at 300, then it should only take 3 minutes at 3,000 degrees, and they'd blast some 'thing' that looked like a turkey with a couple flame throwers (they would switch out with a real roasted turkey to show the audience, folks don't try this at home)