In a medium saucepan, combine the fresh blueberries, sugar, and water. Stir gently to combine the ingredients. This mixture will form the base of your syrup.

Place the saucepan over medium heat and bring the mixture to a gentle boil. This process helps to release the natural juices from the blueberries, creating a flavorful syrup.

Once boiling, reduce the heat to low and let it simmer for about 10 minutes. Stir occasionally, allowing the blueberries to break down and the sugar to dissolve completely.

After simmering, remove the saucepan from heat. Using a fine mesh strainer, strain the blueberry mixture into a clean bowl or another saucepan. This will separate the liquid syrup from the blueberry pulp.

Press down on the blueberries with the back of a spoon to extract as much liquid as possible. Discard the solids or use them in yogurt or oatmeal for added flavor.

Return the strained syrup to the saucepan and add the brewed coffee, lemon juice, and vanilla extract (if using). Stir to combine all the ingredients.

Place the saucepan back on the stove over medium heat. Bring the mixture to a gentle simmer again, allowing it to cook for an additional 5-10 minutes. This step will help to thicken the syrup slightly.

Remove from heat and let the syrup cool to room temperature. As it cools, it will thicken further.

Once cooled, transfer the syrup to a glass jar or bottle for storage. Seal tightly and refrigerate.