Cooking abounds with old sayings and proverbs, which are sometimes useful tips and sometimes myths. We learn or hear them somewhere, and often trust them completely, even when they're wrong.
I propose simply to verify them, to see whether they are real useful tips that we can use, or just ill-founded popular beliefs.
Of course I can't claim to be writing scientific facts here, just personal observations and what I understand them to mean.
The belief
"One should always cover a pan while heating, so that it boils faster".In other words, if you heat water (or something else), it comes to the boil faster with a lid on the pan than without.
The approach
We are going to heat 1 litre of water in an uncovered pan and measure the time it takes to boil , then another litre in a covered pan, heated and measured in the same way.
Comparing these times will tell us if it is really necessary to cover the pan.
Let's check:
1 litre of water is measured and poured into a pan without the lid and put on the hob with a thermometer in it.
Starting temperature of water (and room): 70°F (19°C). | |
The heat is switched on. The water reaches 210°F (100°C) in 9 minutes and 30 seconds. | |
to allow it to reach room temperature again.
Another 1 litre water is put in the same pan covered with the same thermometer in it, on the same hob.
Starting temperature of water (and room): 70°F (19°C). | |
The heat is switched on. The water reaches 210°F (100°C) in 9 minutes and 27 seconds. | |
The result is shown more clearly in the diagram: the temperature of the uncovered pan in red and that of the covered pan in green. | |
Results
The time difference is too small to be significant. It really doesn't matter whether the pan is covered or not.
So, "
One should always cover a pan while heating, so that it boils faster." :
False.
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