MobileRead Forums - View Single Post - Ready meals - why pre-heat the oven?

kacir · 06-26-2009, 01:51 PM

Where to begin ...
Ok.
1. people have very different models of ovens. Some ovens take 5 minutes to reach 180°C, others more than 20 minutes.
2. Person that is more likely to use "TV diner" needs VERY specific instructions regarding preparing the meal, so "Preheat the oven to 180°C, put in tray, cook for 5 minutes" is much better than complicated instruction asking user to take into account the time the oven needs for preheating. Note that if your oven takes 5 minutes to preheat, you will need 5:00 + 4:30 mins, if your oven takes 20 minutes to preheat, you will need 20:00 + 2:00 min (this is just example, real values would need complicated mathematical model of oven, you need to take into account the consistency and thermal capacity of the meal.)

3. make a small experiment. Even a person that only ever cooks Ready made meals should be able to do that one.
Put cold oil into the pan. Put some frozen potato chips (french fries for Americans) (I do not dare to ask you to peel and cut up the potatoes) into cold oil. Slowly heat the oil up until chips are cooked.
Now put oil into pan, preheat to 190°C, put in frozen potato chips, fry until done.
Now compare resulting meal. Quite a difference, isn't it?

If you use ready made meals often, you do NOT want to know how to make the best chips (French fries for Americans) in the world. (Recipe invented by Heston Blumenthal - google him up, if you dare

)
The preparation involves:
- slowly cooking raw potato chips in water
- draining cooked potatoes
- putting them (while still hot) into vacuum desiccator, so you remove as much as possible moisture from outer layers as possible
- putting them into friting pot with oil at 140°C and frying then until almost done
- putting them again into vacuum desiccator
- fritting them at 190°C until golden.
Yes. I have personally tried this recipe. It does not even take that long. (but you still need vacuum desiccator that I replaced by a laboratory oil based vacuum pump). The resulting chips are unbelievably crisp. Almost as it they were made of glass.
There is more simple recipe where you just dry up cooked potatoes in a refrigerator (the driest environment in an ordinary household)

This is only humble deep fried potatoes. Do not let me get started on the topic of meat preparation. Look up, for example Maillard Reaction

Try some recipes here http://www.bbc.co.uk/apps/ifl/food/r...ian&oper_10=eq

06-26-2009, 01:51 PM	#17
kacir Wizard Posts: 3,463 Karma: 10684861 Join Date: May 2006 Device: PocketBook 360, before it was Sony Reader, cassiopeia A-20	Where to begin ... Ok. 1. people have very different models of ovens. Some ovens take 5 minutes to reach 180°C, others more than 20 minutes. 2. Person that is more likely to use "TV diner" needs VERY specific instructions regarding preparing the meal, so "Preheat the oven to 180°C, put in tray, cook for 5 minutes" is much better than complicated instruction asking user to take into account the time the oven needs for preheating. Note that if your oven takes 5 minutes to preheat, you will need 5:00 + 4:30 mins, if your oven takes 20 minutes to preheat, you will need 20:00 + 2:00 min (this is just example, real values would need complicated mathematical model of oven, you need to take into account the consistency and thermal capacity of the meal.) 3. make a small experiment. Even a person that only ever cooks Ready made meals should be able to do that one. Put cold oil into the pan. Put some frozen potato chips (french fries for Americans) (I do not dare to ask you to peel and cut up the potatoes) into cold oil. Slowly heat the oil up until chips are cooked. Now put oil into pan, preheat to 190°C, put in frozen potato chips, fry until done. Now compare resulting meal. Quite a difference, isn't it? If you use ready made meals often, you do NOT want to know how to make the best chips (French fries for Americans) in the world. (Recipe invented by Heston Blumenthal - google him up, if you dare ) The preparation involves: - slowly cooking raw potato chips in water - draining cooked potatoes - putting them (while still hot) into vacuum desiccator, so you remove as much as possible moisture from outer layers as possible - putting them into friting pot with oil at 140°C and frying then until almost done - putting them again into vacuum desiccator - fritting them at 190°C until golden. Yes. I have personally tried this recipe. It does not even take that long. (but you still need vacuum desiccator that I replaced by a laboratory oil based vacuum pump). The resulting chips are unbelievably crisp. Almost as it they were made of glass. There is more simple recipe where you just dry up cooked potatoes in a refrigerator (the driest environment in an ordinary household) This is only humble deep fried potatoes. Do not let me get started on the topic of meat preparation. Look up, for example Maillard Reaction Try some recipes here http://www.bbc.co.uk/apps/ifl/food/r...ian&oper_10=eq