Weigh out equal amounts (a 1:1 ratio by weight) of black sugar and water.
For every 8 ounces, add one vanilla bean pod, sliced open vertically.
Combine all ingredients in a small saucepan over medium-low heat and stir until the sugar is completely dissolved.
Remove the syrup from heat and let sit for 10 minutes. Pass through a fine-mesh strainer with a cheesecloth or coffee filter, and store in an airtight container in the refrigerator. Keeps up to 2 weeks.