Place tea bags, basil leaves, and baking soda in a large glass jar or pitcher.
In a medium saucepan, bring 4 cups (960 ml) of the water to a rolling boil over high heat; immediately pour over tea bags and basil, making sure bags and leaves are submerged. Steep for 15 minutes. Remove basil and bags, gently squeezing them using kitchen tongs; discard bags and bas