Why boiling water ruins delicate teas
Green and white teas are processed with much less oxidation than black tea, leaving more delicate compounds intact — full-boiling water extracts these too aggressively, pulling out excess tannins that make the tea taste bitter and astringent rather than the naturally sweet, grassy, or floral notes these teas are meant to have. Black tea and herbal tisanes are more processed/robust (or, for herbal blends, not tea at all but dried herbs/fruit), so they tolerate — and often need — full boiling water to extract properly.
Getting the right temperature without a thermometer
A simple trick: bring water to a full boil, then let it sit off heat for a specific time before pouring — roughly 30 seconds off the boil gets you close to 200°F, about 2-3 minutes off the boil brings water down closer to the 160-180°F range suited to green and white teas. Electric kettles with adjustable temperature settings remove the guesswork entirely if you brew delicate teas often.
FAQ
Why is the steep time a range rather than one number? Personal taste varies — shorter within the range gives a lighter, more delicate cup, while longer gives a bolder, stronger one. Start at the lower end and adjust to preference.
Does oversteeping ruin tea the way it does coffee? Similarly, yes — leaving tea leaves in too long extracts excess tannins, leading to a bitter, overly astringent cup regardless of tea type.