Some people rinse the Tea leaves once before actually steeping it. Blanching the tealeaves is not a ritual, but rather a step to get a delicious cup of Tea.
This is important because allows the Tealeaves to open up and removes residual microbes that can affect the taste and also enables an effective infusion.
Blanching the Tea leaves is even more important when the Teas are mature or post-fermented. For example phuer Tea are usually blanched twice before the first infusion.
In practical terms, the first brew should be disposed. You blanch the Tea for about a minute and discard the water. You can then start brewing your real Tea.
Happy Tea Break. 🙂