Step 1: Prepare Your Fruit. Wash your berries thoroughly. Hull the strawberries and roughly chop any larger ones. There’s no need to chop the smaller blueberries or raspberries.
Step 2: Blend the Fruit and Water. In a powerful blender, combine the prepared mixed berries with 2 cups of cold water and the fresh lime juice. Blend on high speed until the mixture is completely smooth. This should take about 1-2 minutes.
Step 3: Strain for Smoothness. Place a fine-mesh sieve over a large pitcher or bowl. Pour the blended fruit mixture through the sieve, using the back of a spoon or a rubber spatula to press down on the solids, extracting as much liquid as possible. Discard the pulp and seeds left in the sieve.
Step 4: Sweeten to Perfection. Add the initial 2 tablespoons of granulated sugar (or your preferred sweetener) to the strained fruit liquid. Stir well until the sugar is completely dissolved. Taste the fruit agua fresca. If it’s not sweet enough for your liking, add more sugar, a tablespoon at a time, until you reach your desired sweetness.
Step 5: Dilute and Chill. Add the remaining 4 cups of cold water to the sweetened fruit mixture in the pitcher. Stir to combine. For optimal flavor and refreshment, cover the pitcher and refrigerate for at least 1-2 hours.
Step 6: Serve and Enjoy. Once chilled, give the fruit agua fresca a good stir. Serve over plenty of ice, perhaps with a fresh lime slice or a few whole berries as a garnish.