1) Small Pinhead Bubbles (Shrimp Eyes)
The point where you first start seeing bubbles in the water. This mean that the water is around 155–165oF, making it perfect for delicate green teas.
2) Large Pinhead Bubbles (Crab Eyes)
These are slightly larger bubbles. The important thing to note is that small wisps of steam will start to rise from the hot water. The temperature is roughly 165–175oF.
3) Small Pearls (Fish Eyes)
In this stage, the water bubbles will be the size of small pearls. The rising steam will be stronger. This water is roughly 175–185oF.
4) Streaming Pearls (String of Pearls)
This water is around 185–200oF. The bubbles should be streaming to the top and it should almost be boiling.
5) Raging Torrent (Dragon Eyes)
This water looks like rapids in a raging river. It is bubbling violently with swirling and rolling bubbles. The temperature is 200–212oF, which is the boiling point of water.
by Certified Tea Master Chas Kroll