01 - In a medium saucepan, combine cranberries, sugar, and 2 cups of water. Bring to a boil over medium-high heat, stirring until cranberries burst and sugar dissolves, about 7 to 10 minutes.
02 - Remove from heat and allow to cool slightly. Strain the mixture through a fine mesh sieve into a pitcher, pressing solids to extract all liquid. Discard solids.
03 - Add orange juice, lemon juice if using, and remaining 2 cups of water to the pitcher. Stir thoroughly to blend.
04 - Refrigerate for at least 1 hour. Serve chilled over ice.