When I cook things, such as scallop and salmon, I found that the food may be more tender if I wait till the water boils (at 100 C) and immediately turn the fire lower so that the water is not bubbling in the cook pot and maintain the fire at this level. But I noticed that at this point, there is more steam coming out of the water surface and the steam is far more visible than before.
I think I even test to see if there are in fact more steam by putting the my palm about 12 inches above the cook pot, and verified that in fact, when the fire is at high, there is less steam, but at low, there is more steam. Is there a physics principle that can explain this?
Best Answer
I must admit that I have never noticed this, and indeed it runs somewhat contrary to what I would expect.
It's a suggestion rather than an answer, but when the heat is high there will be a strong updraught of hot air so is it possible that the steam is being carried away from the pan before it has a chance to condense to water droplets? Indeed if the air flow is fast enough the steam might never condense because it would be diluted into the surrounding air before droplet nucleation happened.
By contrast at very low heat the air flow around the pan is slow so the water vapour has plenty of time to condense and form visible droplets.