In a large pitcher, combine the lime juice and 6 Tbs. sugar, stirring until the sugar dissolves. Stir in the water. In a mortar using a pestle, crush the mint sprigs, then stir into the limeade. Taste and add the remaining 2 Tbs. sugar if desired. Cover and refrigerate until well chilled. Serve over ice.
Williams-Sonoma Outdoors Series,
Picnics and Tailgates,
by Diane Rossen Worthington
(Time-Life Books, 1998).