Active Time

　　20 minutes

　　Total Time

　　1 hour

　　Creating a shrub—a vinegar-based syrup—is a quick way to add sweetness and acid to any cocktail. The one used here uses tangy rhubarb and gets a slight kick from fresh ginger. Want a non-alcoholic version? Just skip the gin.

　　

Ingredients

Makes 1 cocktail

　　

For the ginger-rhubarb shrub:

2 pounds rhubarb, cut into 1/4" pieces (about 6 cups)

　　1 (7-inch) piece ginger, unpeeled, cut into 1/4" coins (about 1/4 cup)

　　3/4 cup apple cider vinegar

　　1 1/4 cups sugar

　　

For each cocktail:

2 ounces gin

　　1/2 ounce fresh lime juice

　　Club soda (for serving)

　　

For the ginger-rhubarb shrub:

Step 1

Combine rhubarb, ginger, vinegar, and sugar in a medium saucepan over medium-high heat. Cover and bring to a boil, then reduce heat to low. Cook, stirring occasionally, until rhubarb is completely broken down and strands are visible, 10–15 minutes.

　　

Step 2

Using a fine-mesh sieve or a colander lined with cheesecloth, strain mixture into a glass container. Let cool to room temperature, then chill.

　　

For each cocktail:

Step 3

Combine gin, lime juice, and 1 1/2 ounces reserved ginger-rhubarb shrub in a cocktail shaker. Fill shaker with ice and shake until outside of shaker is frosty, about 30 seconds. Strain into an ice-filled Collins-style glass, filling three-quarters full. Top off with club soda.

　　Do ahead:

　　The ginger-rhubarb shrub can be made up to a week in advance and stored in the refrigerator. The shrub makes enough for 12 cocktails.