And no, the microwave is not a valid option.
Water is much more likely to get supersaturated in a microwave, because water heats up in the middle of the container where there are no nucleation points. And supersaturated water heats the tea leaves above 100ºC, which can affect the flavor.
I don’t believe this to be true.
Edit: since the replies aren’t very polite, let me be more clear. This isn’t a concern. Any modern microwave with a turntable doesn’t have this problem
Hmm… I thought superheating referred to heating water over 100º by pressurizing it, not by heating it at normal pressure without allowing bubbles to form.
Because technically the steam is dissolved in the water above its saturation point, right? If the gas were (say) CO2 instead of steam, wouldn’t “supersaturated” be the correct term?
Because technically the steam is dissolved in the water above its saturation point, right? If the gas were (say) CO2 instead of steam, wouldn’t “supersaturated” be the correct term?
If the gas were CO2 instead of steam, CO2 would be the solute, and water the solvent. In that case the term supersaturated would make sense because the solvent contains more solute than it can handle under normal conditions. The steam is not disolved in the water. The microwaved water is unable to form steam in the first place due to a lack of available nucleation sites.
I thought superheating referred to heating water over 100º by pressurizing it
That isn’t superheating. The boiling point of a given substance naturally varies with pressure. Liquid water at 200oC while pressurized sufficiently isn’t superheated. It is just hotter than you expect it to be. That technique can be used to superheat something like water if heated over it’s atmospheric boiling temperature while pressurized and then lowering the pressure without agitating it.
It would only be able to heat the tea to above 100C if that point of zero nucleation remained undisturbed, and the tea held directly within it; in other words, it’s not possible.
Assuming there’s an amount of water within the cup that is above 100C, while the rest is at or below 100C. As soon as you grab the cup out of the microwave, the water will start to slosh around in the cup, equalizing the temperature. If there are any major hot spots remaining, they will be well below 100C, and almost completely equalized when the tea bag is added.
It would only be able to heat the tea to above 100C if that point of zero nucleation remained undisturbed, and the tea held directly within it; in other words, it’s not possible.
To be clear, the liquid water flashes into steam as soon as it contacts the leaves, so technically it isn’t the supersaturated water itself heating the tea over 100º. But the steam it produces is above 100º, and that’s what heats the tea.
