In a medium sized saucepan, combine elderberries, cinnamon, and 4 cups water. Over medium heat, bring to a boil. Once boiling, reduce heat to low and simmer for 45 minutes to 1 hour. Liquid should reduce to half.

Using a potato masher, mash the berries. Using a fine mesh strainer, strain the berry components from the liquid.

Stir the honey into the liquid elderberry juice until dissolved. Next, stir in the apple cider vinegar. Transfer to a glass jar with a lid. Let cool at room temperature.