Water conducts heat faster than air. That's why 70 degree water is much colder on your body than 70 degree air is. Ice in a cooler melts because of the heat that transfers through the cooler. If there is water in the cooler, it will transfer that heat to the ice faster than if just air was in the cooler.
However, keeping food colder is better done with water because the water conducts the heat away from the food to the ice, (melting the ice) faster than air conducting the heat out of the food.
So, Drain and the ice should last longer but the food not be as cold. Don't drain the the food will be better chilled but the ice won't last as long.
Which ice chest holds the colder beer; the one filled with ice and water, or the one filled with just water? Ice and water obviously.
