Makes 2 drinks (can easily be doubled)
Three 4-inch-long slices English cucumber2-inch piece ginger root, peeled and thinly sliced
1/2 cup raw sugar
Put one of the cucumber slices in the seltzer bottle. Let sit while you make the drink.
Put the ginger, sugar, and 1/2 cup water in a saucepan. Bring to a boil and cook for 5 minutes, stirring if needed. Strain and let cool completely.
Fill two tumblers halfway with ice. Add 3 tablespoons ginger syrup to each glass. Fill the glass with the seltzer -- and stir and taste as you go -- add just enough seltzer to make the drink as sweet and gingery as you like. Garnish each glass with a cucumber slice.