http://www.quooker.dk/dk/img/Energir...april-2010.pdf
..there is a danger of ‘superheating’, especially when using very smooth, scratchless surfaces, e.g. a new tea glass, and especially when the water has been previously heated and most of the dissolved gases have been driven out. The liquid does not find any irregularities that can serve as a nucleus for forming water vapour bubbles and actually will not ‘ bubble’ easily. The temperature can then rise above the boiling point (e.g. 101 °C). Once the cup is picked up or the surface is slightly stirred by adding a substance (coffee, tea) this one degree of superheating results in instantaneous flash-evaporation of water (amounting to about 3 litre of water vapour per litre water of 101 °C), causing the boiling water to splash from the cup possibly causing serious burning injuries.
In an aircraft at altitude you would probably have to turn the temperature down because if you put water at say 98C into a cup when the local boiling point is only 92 it's going to bubble away like mad...that is if you can get the water into the cup without it turning to steam as it comes out of the tap?