Use a rolling pin or tenderizer to smash the lemongrass. Bring the agave and water to a boil in a small saucepan and add the lemongrass. Remove from heat and cool completely. Strain and discard the lemongrass.

Working in batches, combine the blackberries with 2–4 cups water in a blender and purée. Strain through a fine-mesh sieve or cheesecloth to remove seeds and pulp. Add the simple syrup to the strained juice and dilute with 8–10 cups water. At this point you can adjust the drink to your liking with lime juice, adding a pinch of salt and additional agave or water as desired. Serve over ice with sliced lemongrass and blackberries for garnish.

Courtesy of Edible San Diego. Recipe by Miguel Valdez. Photo by Olivia Hayo, styled by Gary McIntire.