Combine cider and brown sugar in a large saucepan. For a spice bag, tie cinnamon, allspice, cloves, and lemon peel in a 6-inch square of 100 percent cotton cheesecloth. Add spice bag to cider mixture. Bring to boiling over medium-high heat; reduce heat. Cover and simmer for 15 minutes. Remove and discard spice bag.
Top each serving with 1/2 teaspoon butter and serve with a cinnamon stick stirrer, if desired. Makes 10 to 12 servings.