Cookbook author Amy Thielen likes to add a splash of this tart, naturally fizzy juice to grown-up, not-too-sweet ice cream floats for a bright swath of flavor. You might also like mixing it into cocktails and even vinaigrettes. You can start with any fruit, but the smaller and juicier the better.
Makes 3 cups
10 oz. frozen raspberries, thawed
1⁄3 cup sugar
1 tbsp. fresh lemon juice
 In a bowl, stir the raspberries with the sugar and 2 cups boiling water until the sugar dissolves. Let stand until cooled to room temperature, about 30 minutes.
 Pour the raspberries and liquid through a fine sieve set over a bowl and stir, without pressing the berries, until drained. Discard the spent raspberries or save for another use. Stir the lemon juice into the raspberry juice and cover with plastic wrap. Let stand at room temperature until fizzy and fermented, about 5 days.
 Uncover the raspberry juice and pour it through a fine sieve lined with cheesecloth into a small pitcher. Cover with plastic wrap and refrigerate until ready to use.