Bring 4 cups of water to a rolling boil in a medium saucepan, then remove from heat.
Add the tea bags and a pinch of baking soda. Steep for 10 minutes for a smooth, balanced brew.
Carefully remove and gently squeeze tea bags to extract every bit of flavor.
While the tea is warm, whisk in the sugar until completely dissolved.
Pour the concentrate into a large pitcher and add the remaining 4 cups of cold water.
Refrigerate for at least 2 hours until well chilled.
Serve over ice, garnished with lemon slices or mint, and enjoy!