Bring the water to a boil, then remove from heat and let it cool slightly to about 95°C / 203°F. Add the black tea bags and steep for 3–4 minutes only, then remove the bags without squeezing to prevent bitterness.
While the tea is still hot, add the light brown sugar and stir until fully dissolved, then add the lemon zest. Cover and let steep for 10 minutes so the citrus oils infuse aroma without pushing acidity.
Strain the tea through a fine-mesh sieve into a bowl or measuring jug, removing all zest. Let the lemon tea extract cool completely.
Pour the cooled lemon tea extract into a large pitcher, add the fresh lemon juice and the ice-cold water, and stir gently until fully combined and clean.
Refrigerate for 1–2 hours until fully cold and the flavors are integrated.
Fill glasses with ice, pour over the lemon iced tea, and garnish with lemon slices and lemon peel twists.
