To make the blackberry hibiscus syrup, add water and sugar to a medium saucepan over medium heat. Stir until the sugar dissolves, then add the blackberries. Bring the mixture to a boil, reduce heat to medium-low, and cook berries until they break down and release their juices (about 5 minutes). You can use a fork or masher to help break up the berries while they’re cooking. Return the pan to medium heat, stir in the dried hibiscus, then bring the mixture back to the boil. Take the mixture off the heat, and let cool completely. Pour mixture through a fine-mesh strainer into a clean jar.

To make the cocktail, combine 1 ounces of blackberry hibiscus syrup with tequila and lime juice in a short tumbler filled with ice, stirring to combine and chill. Add the soda water, and gently stir to combine. Garnish with a lime wedge and some blackberries.