Xu Ci Xu, Ming dynasty scholar, author of the book Cha Shu – Tea Sort.
One section is dedicated to boiling water. Literal translation:
Best choice is hard wood charcoal. Charcoal may not be fully carbonized, smoke may be present when burning, odorizes the water, hence water is not good. Let the charcoal burn to amber, rid of smoke, the heat is at prime, water is fast to boil. When the charcoal is amber, put on the kettle, fan with fury, the faster the better, do not stop. If stop, discard and start a new pot.
Tea is nourished by water, water is placed by kettle, boiling water is succeed by fire, 4 essential elements in tea making, one falls short will fail all.
I can see why I speak broken English now! :D
The old Chinese text are precisely concised, but incredibly poetic and expressive, however direct translating to English is a whole different presentation, not quite as eloquent as it sounds in Chinese.
So what it means is that use hardwood charcoal, because the density of the wood, it burns longer and the heat is higher in temperature. But most charcoal still contains organic materials residues other than carbon, smoke will be released at burning initially. Allow the charcoal burn to red amber, until smokeless, at this point, the heat is at prime, it can bring the water to boil fast. Only put the kettle on the fire when the charcoal is amber with flame, continue to fan the stove, faster the better and do not stop until the water boils. If fanning is interrupted, the water is no longer good enough, start a new pot. Momentum! Momentum! Use full force whole heartily! Use up the water one boiled kettle at a time, also do not reboil cooled off water. This is why Chaozhou Sha Diao are made to contain only a couple brews worth of water volume. One reason why I didn't like water boiled from large kettles, tea made from it taste sluggish and muted, in other words, lack of livelhood, lack of vital energy.
There is tea drinking, there is serious tea drinking, and there is optimal tea drinking. The best possible way to make an ideal cup of tea has been documented centuries ago. We may have all the elements, however we must know how to operate them to get the best results.
The serious tea drinkers may know the tangibles such as tea selections and tea wares, but it is the intangibles we must learn from experience, either from our own practice, perceive with our own body, our own senses and mind, or learn and digest from others. It may take a long time to reach the optimal, but it's an understand and sensation one can not forgo once the practice becomes apparent and with ease.
Laying out all the elements, the materials and the operating method, the picture clearly puts everything into track, once again law of nature, the fundamental of universe, transformation of energy! In this case, maximizing the energy and its effects between earth/metal, water, wood, fire and human!