Japanese Soda Recipe

Basic Syrup

Combine 1 cup granulated sugar and 1 cup water in a small saucepan over medium heat. Stir until the sugar fully dissolves and the mixture comes just to a simmer (do not boil hard).

Add Flavor

Remove saucepan from heat. Stir in 3 tablespoons yuzu juice (or the lemon+orange substitute), 1 tablespoon thinly sliced fresh ginger, and 2 tablespoons ume syrup (or 2 tablespoons concentrated umeboshi paste dissolved into the syrup). If using shiso, add the torn leaves now and let steep for 10–15 minutes to infuse aroma and a mild herbaceous note.

Strain and Cool

After 10–15 minutes, strain the syrup through a fine-mesh sieve into a heatproof container, pressing gently on solids to extract flavor. Discard solids. Let the syrup cool to room temperature, then refrigerate until cold (at least 30 minutes). Syrup will keep refrigerated for up to 2 weeks.

Fill each serving glass with about 3–4 ice cubes (adjust per glass size).

Measure out 2–3 tablespoons of the prepared flavored syrup per 8 oz (1 cup) serving. Pour the syrup over the ice in each glass. Taste and adjust: use 2 tbsp for a light flavor, 3 tbsp for more pronounced sweetness and acidity. If you prefer sweeter, add up to 1 tsp simple syrup.

Top each glass with 1 cup club soda (or a mixture of 3/4 cup club soda + 1/4 cup cold sparkling water for extra fizz). Stir gently once to combine without losing too much carbonation.

Garnish each glass with one fresh shiso leaf tucked into the side and a yuzu or lemon wheel on the rim. For a ginger accent, float a thin slice of fresh ginger.

Serve immediately with a straw or stirrer so guests can adjust sweetness. For variety, offer extra syrup on the side and a small bowl of crushed ice.