that if it does leak (if you use the zipper bag method), you will not have alcohol in your food. place the container in the bottom of the ice chest, and then pack your food around and over the top of the plastic container.
the ice pack will keep your food cold as long as, and sometimes longer than, a bag of ice would. for large ice chests, you might need to use more than one container with homemade ice packs in them to keep the food as cold as you need it to be, especially on really hot days.
have you ever made your own homemade ice bags? 