Combine sugar and 2 cups water in a saucepan over medium heat. Bring to a boil and stir until sugar has dissolved. Remove from heat and cool to room temperature.
Strain the lemon juice through a fine-mesh sieve into a 2-quart pitcher. Add simple syrup and stir to combine. Refrigerate until cold.
When ready to serve, add 2 1/2 cups of cold water and stir. Taste, and add more water if it's too sweet. Serve over ice, if desired.
Yield: Makes about 7 cups of lemonade.To Make Ahead: This easy lemonade recipe can be made and kept covered in the fridge up to a day or two in advance. Store leftovers in the fridge for up to 7 days (but I promise it won't last that long!).To Freeze: You can freeze the lemon juice concentrate from this recipe and save it to make homemade lemonade, any time. Mix the cooled simple syrup and fresh squeezed lemon juice together. Pour into a freezer bag and freeze for up to 5 months. Allow the mixture to thaw and add it to a pitcher. Add water, to taste, until you reach your desired sweetness.