3/4 cup granulated sugar
3/4 cup water
2/3 teaspoon root beer concentrate
1 liter cold seltzer water
1. Heat or microwave the water until it is very hot, but not boiling. Dissolve the sugar in the hot water until it disappears.
2. Add the root beer concentrate to the sugar water and let the mixture cool to room temperature. Combine the mixture with the cold seltzer water.
Stir well and refrigerate in an airtight container until ready to serve.