Water temperature also influences the final cup, and tea masters are vigilant about heating their water optimally to match the tea they are brewing. However, they determine the “readiness” of the water in different ways-visually, auditorially, and electronically.
Some look for visual signs of the water temperature to determine when the water is heated properly for the particular tea they intend to brew.
You may have heard tea masters talk about looking for “fish eyes” in the water. This is when medium bubbles form just before the water moves towards a roiling boil. This is when the water is ready for oolongs, generally. The way the steam leaves the spout of the kettle—in wisps or in gusts–also signals the water’s readiness for some tea masters.