F&W's Grace Parisi makes this soda with iSi's new Twist'n Sparkle soda maker, which carbonates beverages in less than 30 seconds. $50; williams-sonoma.com
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In a medium saucepan, simmer 1 cup water with sugar until the sugar is dissolved. Add basil and mint leaves and let steep for 1 hour.
Strain and discard the herbs. Let the syrup cool completely. Stir 4 cups cold water and fresh lime juice into the syrup.
Make the soda according to the manufacturers' directions. Serve in tall glasses over ice.