Some tea people are mindful of this, and go out of their way to find or create just the right heating element. Possible sources for heat include charcoal fire, wood fire, electric coil (stove), gas range, and ceramic heat, among others including electric plug-in appliances.
In earlier times, and still now in some parts of the world, people had no choice but to heat water over a wood or charcoal fire. From experience, I can say this does enhance the pleasure of a tea event, but how does it influence the tea itself? Does it matter if you boil tea over a hot flame or stove or more slowly at a medium high temperature?
According to Lu Yu, author of The Classic of Tea (Cha Ching) in eighth century China, "The ancients placed a great store in tea's flavor when it was brewed with firewood that had been cured for a long time." If using charcoal, he said, be sure to use new charcoal so that it does not "give off a musty, rank and greasy smell". He also advised against using "oily wood or worn-out or discarded utensils as fuel."
It is hard to know what he would have thought of a gas or electric range or a Zojirushi, but my guess is that he would think electricity to be too excitable for the best in tea.
Some people think electricity disturbs the energy of the tea water and that a wood or charcoal fire lends a natural element which cannot be duplicated by nuclear generated power. Whether these enhance the tea itself is up for speculation. Any comments?