Make the simple syrup. Over med-high heat, add the sugar and water into a small saucepan. Continuously stire the mixture until the sugar is completely dissoved. Set aside and let cool.
Juice Grapefruits with a citrus juicer. Strain with a fine mesh sieve to remove seeds and pulp.
Sweeten juice with simple syrup. Add simple syrup to the grapefruit juice. Stir.
Serve with ice and sparkling water. ***Equal parts juice and sparkling water is recommended. Stir and enjoy!
Optional: Garnish with mint, rosemary, and/ or grapefruit slices.
Notes
●Simple syrup can be made and stored in sterilized containers for up to 1 month in the fridge. ●We found that grapefruit juice gets more bitter as it sits. So If you are a fan of that grapefruit bitterness, just let the juice sit in the fridge for a couple of days.