Run a grapefruit wedge or lime wedge around the rim of a highball or Collins glass to moisten. Spread the coarse salt on a small plate, then dip and twist the glass rim into the salt so it adheres evenly. Set the glass aside.

Build the Cocktail

Combine base ingredients

In a cocktail shaker, add 1 oz blanco tequila, 2 oz fresh grapefruit juice, 0.5 oz fresh lime juice, and 0.5 oz demerara syrup. Fill the shaker with ice (about 1 cup cubed).

Shake

Shake vigorously for about 10–12 seconds until the outside of the shaker is cold and slightly frosted. This chills and dilutes the mixture appropriately.

Strain over ice

Fill the prepared glass with fresh ice. Double-strain the shaken cocktail into the glass (use a Hawthorne strainer and a fine mesh if available) to remove ice shards and pulp.

Top with soda & garnish

Top the drink with 2 oz club soda, gently stir once or twice to integrate. Garnish with a grapefruit wedge and a lime wheel on the rim. Serve immediately.

Optional Batched Preparation (4 servings)

In a pitcher, combine 4 oz tequila, 8 oz fresh grapefruit juice, 2 oz fresh lime juice, and 2 oz demerara syrup. Stir or gently roll to mix. Keep chilled. When ready to serve, fill each rimmed glass with ice, pour 2 oz of the mix into each glass, top each with 2 oz club soda, stir once, and garnish.