Prep the Citrus: Wash and halve your limes (and lemons if using). Use a citrus juicer or reamer to squeeze out 1 cup of fresh lime juice. Strain through a fine-mesh sieve to remove pulp and seeds for a smooth mix.

Make the Simple Syrup: In a small saucepan over medium heat, combine the water and sugar (or agave). Stir occasionally until the sugar fully dissolves – about 3-5 minutes. Don’t boil; just simmer gently. Remove from heat and let cool for 5 minutes.

Combine Everything: In a large pitcher or mason jar, mix the cooled syrup with the fresh lime juice and a pinch of salt. Stir well to blend the flavors. Taste and adjust – add more sweetener if it’s too tart, or a splash more juice for extra zing.

Chill and Store: Pour into an airtight container or bottle. Refrigerate for at least 30 minutes to let the flavors meld, though it’s ready to use immediately if you’re in a hurry.