Add sugar, water, and lemon peel to saucepan. While stirring constantly with a wooden spoon, bring mixture to boil for 5 minutes. remove saucepan from stove and let cool. Squeeze 1 1/2 cups lemon juice and add to the cooled sugar and water mixture.
Pour lemonade syrup into a jar and cover with lid. Syrup can be kept in refrigerator for 2-3 weeks.
If making the entire amount at once, in a pitcher combine the 10 1/2 cups water with all the lemonade syrup over the ice cubes and stir.
Place lemon slices as well.
**To make individual glasses**.
Place two ice cubes in bottom of glass. Pour 1/4 cup of lemonade syrup over ice cubes. Add 3/4 cup of cold water and stir. Place lemon slice on top and fresh mint if desired.
**For pink lemonade add 1.2 grenadine syrup to jar and shake**.