1 1/2 cups water, or as needed to cover
4 large lemons, juiced
1 cup white sugar
7 cups water, or as needed
16 leaves fresh mint, crushed
Place ginger into a blender, cover with 1 1/2 cup water, and blend until ginger is thick and pasty. Strain and squeeze juice from ginger pulp into a 2-quart pitcher, squeezing ginger mixture as dry as possible. Stir lemon juice and sugar into ginger juice until sugar has dissolved. Pour 7 cups water into mixture, stir to combine, and serve garnished with crushed mint leaves.