Dietary guidance: v v
3 cups water
2 cups sugar
2 cups thinly sliced fresh ginger (1/2 lb; from a 10-inch piece), left unpeeled
Bring water, sugar, and ginger to a boil in a 2-quart saucepan, then stir until sugar is dissolved. Simmer 10 minutes, stirring occasionally, then remove from heat and let steep 15 minutes. Pour ginger syrup through a sieve into a bowl, discarding ginger. Chill, covered, at least 2 hours.
Syrup keeps, covered and chilled, 2 weeks.