Making Margaritas for a large group? Use this big batch recipe! Margaritas by the Gallon: 6 cups tequila (you'll need to buy two fifths for this), 2 cups triple sec (just buy one fifth), 2 cups fresh lime juice, 2 cups fresh lemon juice, 2 cups simple syrup. *Mix ingredients together in gallon container. Don't forget to refrigerate! When ready to serve, pour mixture into a 16-oz glass filled with ice. Salted rim is optional. Makes 21 margaritas.