Prep the pineapple. Peel, core, and chop the fresh pineapple into chunks. If using canned pineapple, drain it and reserve a few tablespoons of the juice for extra flavor.

Blend the base. Add pineapple to a blender with 1/2 cup sugar, 2 tablespoons lime juice, a pinch of salt, and 2–3 tablespoons water or reserved pineapple juice. Blend until completely smooth.

Taste and adjust. Sip a little. If it’s too tart, add more sugar. If it’s too sweet, add a splash of lime. The mixture should taste slightly sweeter than you want the final soda, since you’ll dilute it with bubbles.

Strain (optional but recommended). Pour the puree through a fine-mesh strainer into a bowl or pitcher. Press with a spoon to extract as much syrup as possible. This gives a cleaner, smoother soda.

Chill the pineapple syrup. Refrigerate for at least 30 minutes. Cold syrup keeps the soda extra fizzy when you mix it.

Build the soda. Fill a glass with ice. Add 3–4 tablespoons of pineapple syrup. Top with very cold sparkling water. Gently stir to combine. Taste and adjust syrup to your liking.

Garnish and serve. Add a squeeze of lime, a sprig of mint, or a thin pineapple wedge if you like. Serve immediately while it’s lively and bubbly.