Citrus-Beer Punch

Juice the lemons and thinly slice the peels. Stir the sugar and the water in a saucepan and bring to the boil. Add the lemon peels, remove from the heat and cover for 5 minutes. Then remove the peels and add the lemon juice and the grapefruit juice. Stir and transfer in a pitcher. Cover and chill for about 3 hours. Just before serving add the beer. Serve over ice in beer mugs and decorate with lemon slices. This punch makes approximately 8 servings.