Bring the water to a boil, then remove from heat and allow it to cool slightly to about 95°C / 203°F. Add the black tea bags and steep for 3–4 minutes only. Remove the tea bags without squeezing — squeezing releases tannins and will make the final pitcher harsh and drying.
While the tea is still hot, add the light brown sugar and stir until completely dissolved. Sweetening at this stage ensures even distribution and prevents grainy texture later.
Add the lemon zest and raspberries to the hot, sweetened tea. Gently mash the raspberries just enough to crack them and release aroma — do not crush into a paste. Cover and let steep for 10–15 minutes. The residual heat extracts color and aroma without cooking the fruit or dulling freshness.
Strain the mixture through a fine-mesh sieve into a bowl or large measuring jug. Press very gently to extract liquid, but do not force pulp or seeds through. Discard all solids and let the raspberry tea extract cool completely.
Pour the cooled raspberry tea extract into a large pitcher. Add the ice-cold water and stir gently until fully combined.
Refrigerate for 1–2 hours until fully cold and flavors are integrated.
Fill glasses with ice, pour over the raspberry iced tea, and garnish with fresh raspberries and optional lemon peel twists.
