Combine 2 cups granulated sugar and 1 cup water in a small saucepan over medium heat. Stir until sugar dissolves and the mixture comes to a gentle simmer. Continue simmering 2–3 minutes until slightly thickened, then remove from heat.

Season and acidify

Stir in 1 tablespoon fresh lime juice and 1 teaspoon kosher salt into the hot syrup. Allow syrup to cool to room temperature (about 20–30 minutes). Chill in refrigerator if not using immediately.

Flavoring (yields concentrated flavor for 2 L batch)

Prepare fruit or concentrate

If using fresh fruit: peel and chop 1 cup fruit (for tamarind, remove seeds and membrane; for pineapple, core and chop). If using frozen concentrate or puree, measure 1 cup thawed concentrate.

Blend flavor

Place the 1 cup prepared fruit or concentrate with 1/4 cup water and any optional additions (1/2 tablespoon grated ginger or a small handful steeped hibiscus petals) into a blender. Puree until smooth, about 30–60 seconds.

Strain (optional)

For a bright, clear Jarritos-style soda, strain the puree through a fine-mesh sieve into a bowl, pressing solids to extract as much liquid as possible. Discard solids. You should end up with roughly 3/4 to 1 cup of concentrated flavor.

Combine flavor with syrup

Mix the cooled simple syrup with the strained fruit concentrate. Taste: this concentrate will be sweeter and stronger than final soda. Adjust sweetness or acidity by adding up to 1 tablespoon more lime juice or up to 2 tablespoons water if too thick.

Carbonation & Finish (makes 2 liters finished soda)

Prepare bottle

Chill the 2-liter bottle of carbonated water so the soda will stay fizzy when mixed. Place 2 cups of ice in a large pitcher or divide among serving glasses.

Mix soda

For a Jarritos-style intensity, use about 3/4 cup of the flavored syrup concentrate (syrup + fruit) per 1 liter of carbonated water. For 2 liters, add 1 1/2 cups of the flavored syrup concentrate to the chilled carbonated water. Stir gently with a long spoon to combine — avoid vigorous stirring to conserve carbonation.

Serve

Pour over ice, garnish with lime wedges, and serve immediately. Offer extra syrup on the side for those who prefer a sweeter or stronger flavor.