To cool cans or bottles, 8-10 pounds of ice per case keeps them cold for 6-8 hours
To cool a half-barrel of beer, 40-50 pounds of ice keeps it cold for 6-8- hours.
For high temperatures and humidity, be sure to get and extra bag or two!
For a tailgate party, have lots of ice on hand with separate coolers for the food and the ice. Have enough ice to keep the food properly chilled until you are ready to cook. Keep the drink ice separate too, so that people aren’t using the ice that has been in contact with hands, cans, and other unsanitary items.