Boiling eggs question

[boblalux]

If I boil (separately) 2 equally sized and equal age eggs, for the same length of time, but the water of one boiling furiously, and the other boiling more slowly (ie both at 100°C), does the hardness of the resulting egg remain the same?

[Enthalpy]

Hi boblalux, welcome!

 

Is essence, the same heat transfer because of the same temperature. There can be minute differences as stronger water movement may improve marginally the heat transfer to the egg.

 

Whether the egg gets harder... Because of its movements? I'd say it's a matter of heat in the first line.

 

So you can save electricity without any penalty. Covering the pan is even better, except that water overruns easily.

[EdEarl]

If all else is the same, the two eggs will harden equally. However, the eggs sit on the bottom of the pan and the egg in a fast boiling pan may pick up additional heat from the bottom of the pan and harden a bit quicker. However, the gain is small for the amount of energy lost by boiling quickly.

[Enthalpy]

After all...

 

The boiling water transfers heat much more efficiently that the egg material in the shell, which is the limiting factor. Shaking the egg improves this limiting transfer, so strong boiling could harden the egg a bit faster.

 

Anyway, I'll continue to save electricity by boiling as faintly as possible.

[StringJunky]

After all...

 

The boiling water transfers heat much more efficiently that the egg material in the shell, which is the limiting factor. Shaking the egg improves this limiting transfer, so strong boiling could harden the egg a bit faster.

 

Anyway, I'll continue to save electricity by boiling as faintly as possible.

I think the heart transfer throughout the egg will be more even to the centre, done lightly energy-wise. If you cook something too hot, you can get a gradient of the food being cooked correctly towards the outside but not done in the middle... think of toasted bread.

[Delta1212]

I think the heart transfer throughout the egg will be more even to the centre, done lightly energy-wise. If you cook something too hot, you can get a gradient of the food being cooked correctly towards the outside but not done in the middle... think of toasted bread.

But if it's in boiling water, the temperature is going to be the same regardless of the heat underneath it. The water is exposed to additional heat, but the egg won't be until the water boils off.

Edited April 8, 2016 by Delta1212

[StringJunky]

But if it's in boiling water, the temperature is going to be the same regardless of the heat underneat it. The water is exposed to additional heat, but the egg won't be until the water boils off.

Good point, Delta. Yes, it's self-limiting, of course..

[J.C.MacSwell]

If I boil (separately) 2 equally sized and equal age eggs, for the same length of time, but the water of one boiling furiously, and the other boiling more slowly (ie both at 100°C), does the hardness of the resulting egg remain the same?

Good question. I would expect that the more stable boundary layer of the latter, which would be slightly less than 100 C, especially in the beginning when the egg is cooler, would slow the heat transfer more than the furiously boiling water.

 

I think this would weigh more heavily than the partially vaporized boundary layer of the former case conducting less than that of the latter.

 

It would be interesting to see if there were any experimental results as a number of factors are at play.

Edited April 9, 2016 by J.C.MacSwell

[Enthalpy]

But if it's in boiling water, the temperature is going to be the same regardless of the heat underneath it. The water is exposed to additional heat, but the egg won't be until the water boils off.

 

The difference I see (which should be small) is that with more movement, heat will spread more easily within the egg from the same +100°C.

 

Heat exchange from the boiling liquid to the solid is known to be excellent, among others because vapour bubbles can condense at the solid to transfer as much heat is needed to keep it at +100°C. As opposed, the viscous egg interior is definitely less efficient in removing heat, and is the limiting factor - agreed, MacSwell.

 

So movement shall accelerate cooking, but little, because under the shell where the egg is already solid it won't change anything.

 

So I continue to save electricity by boiling the water as gently as possible.