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 to avoid extracting excess tannins that would dull both the tea and citrus.
While the tea is still hot, add the light brown sugar and stir until fully dissolved. Add the lemon zest and lime zest, cover, and let steep for 10 minutes. This infusion builds citrus aroma and oily depth without adding additional acidity.
Strain the tea through a fine-mesh sieve into a bowl or measuring jug, removing all zest. Let the citrus-infused black tea extract cool completely before assembling the pitcher.
Pour the cooled extract into a large pitcher. Add the fresh lemon juice, fresh lime juice, and the ice-cold water. Stir gently until fully combined, keeping the structure lemonade-forward with tea as a supporting layer.
Refrigerate for 1–2 hours until fully cold and flavors are integrated.
Fill glasses with ice, pour over the iced tea lemonade, and garnish with lemon and lime slices.
