You are about to have a party, a picnic, or go on a camping trip and you need to use a large amount of ice in order to keep your drinks and various food items cold. Having a freezer is a great ally in this quest but not feasible at this time so you are challenged to find a way to keep your ice from melting as long as possible. There are a number of solutions that you can take to solve your problem.
Perhaps your first line of defense is the container in which your ice will be stored. Containers can come in Styrofoam form, nylon lined fabrics, hard thick plastic, and thermal insulation. If you are throwing a party or having a picnic, then the Styrofoam and nylon lined fabric containers would be most suitable for these occasions. However, if you are going on a camping trip for a few days, then a hard thick plastic container with a heavy, well sealed lid or a thermal lined insulation container would be your best option. It is also important to note that the color of your container can play a part in keeping the interior contents cooler and helping your ice to last longer. Darker colored containers tend to absorb more heat than lighter colored containers, so keep this in mind when you make your purchase. To make it even more effective, try lining the interior of the container with aluminized bubble wrap which can be found at your local hardware store. In lieu of the bubble wrap, you can use old newspapers.
Your next line of defense is the ice itself. Ice cubes that come from your refrigerator are often filled with air pockets and, therefore, will tend to melt more rapidly. Try boiling your water first before placing them in the ice trays as the boiling will help eliminate the air pockets and make the ice last longer. Larger chunks of ice will also last longer so, if at all possible, use blocks of ice rather than crushed ice, ice cubes, or ice chips. When cubes or chips are needed as additives for your drinks, then place larger blocks of ice on the bottom of your container first and then fill in the remaining space with the smaller sized ice. In case of a camping trip, layer the bottom and sides of the container with the larger blocks of ice and then fill in the remaining space with the smaller ice chips. You may also want to try freezing your water bottles and then intermittently place the frozen water bottles among the food being stored. The bottled water will thaw slowly and keep the food cold but be ready for drinking when the time comes.
Contrary to popular belief, adding salt to your container will not keep the ice from melting. In fact, salt melts ice. It does, however, help to keep the ambient temperature of the melted water colder, thereby keeping the contents of your container colder as well (although a bit messy). So, now that you are ready to store your ice and extend the time it will take for it to melt, you can sit back and relax and enjoy your party, picnic, or camping trip knowing that your ice will remain for as long as you need it.