This recipe does involve some cooking, but no fermenting is required; you can whip up the syrup in 20 minutes, combine it with soda water, and be sipping within the hour. The recipe scales very well; if you want more than 6 glasses, double the recipe.

Steps

1. Combine berries, sugar, water, and cinnamon stick in a heavy, deep saucepan; cover and bring to a boil over medium-high heat. Reduce heat to a simmer and cook for 15 minutes. Remove berries from the heat, stir in the lemon juice, and let mixture rest for 20 minutes.
2. Using a fine-mesh strainer or a cheesecloth-lined bowl, strain the syrup, and discard the solids. (Or you may wish to reserve them for topping vanilla ice cream later.)
3. To make sodas, fill glasses halfway with ice. Add blueberry syrup and top with soda water (we like about 1 Tablespoon syrup for every 2 ounces of sparkling water, but you may want to play with the ratio that suits you best, depending on how sweet you prefer your soda). Stir well. Top off with ice, add a straw, and sip.