Combine sugar, water and ginger in a small saucepan. Bring to a boil over medium heat, stirring to dissolve the sugar. Boil for about 30 seconds. Remove from heat, cover and let cool to room temperature, about 1 hour. Strain the syrup, discarding the ginger.Advertisement
For each drink, muddle 5 mint leaves with 1 1/2 ounces bourbon in an 8-ounce glass or chilled copper mug. Add 3 tablespoons lime juice and 1 tablespoon of the syrup. Fill with ice and top off with 3 tablespoons ginger beer. Garnish with a mint sprig and lime wedge, if desired.
To make ahead: Refrigerate syrup (Step 1) for up to 1 month.