Chill your glass. Pop a highball or stemless wine glass in the freezer for 5–10 minutes.
A cold glass makes a big difference in summer heat.
Prep your citrus. Juice fresh limes and grapefruit. Strain out the pulp if you like a smoother sip.
Muddle the mint lightly. In a shaker, gently press 6–8 mint leaves with a tiny pinch of sea salt. Don’t shred them—one or two presses to release oils is enough.
Add the base. Pour in 1.5 oz vodka or gin, 1 oz fresh lime juice, 2 oz grapefruit juice, and 0.5–0.75 oz simple syrup (adjust for sweetness).
Add ice.
Shake briskly. 8–10 seconds is perfect. You want it frosty but not over-diluted.
Strain and top. Strain into your chilled glass over fresh ice. Top with 2–3 oz sparkling water for lift.
Garnish with intention. Clap a mint sprig between your palms to release aroma.
Add a grapefruit wedge or lime wheel. Finish with one small pinch of salt over the top if you like—it brightens the citrus.
Taste and adjust. If it’s too tart, add a splash more syrup. If it’s too sweet, more lime or a bit more soda evens it out.