Combine cranberries, water and lemon slices in a stainless steel or enamel saucepan. Bring to a boil; reduce heat and simmer uncovered 30 min. Add sweetener, stir until dissolved. Strain, stirring and mashing berries until a fairly dry pulp remains in strainer. Store concentrate in refrigerator. OR Freeze in a shallow square pan. Cut it into 8 equal blocks, then wrap and store them in the freezer. OR freeze in a plastic ice cube tray that holds 2 cups and makes 16 cubes. CRANBERRY REFRESHER Dilute 1/4 cup concentrate (1/8 recipe or 2 ice cubes) with 3/4 cup water, sugar-free ginger ale or soda water. 1 cup serving 1 ++ extra, 12 calories 3 g carbohydrate