The science of cooler stewardship—i.e. taking care of your cooler—has reached its zenith. Why? Because anyone who will spend $100 or more on a cooler is going to do his or her research! These newer coolers aren’t as high maintenance as old-school Coleman’s and will keep ice fresh for days on end, but they still require care and common sense to make sure your gear is performing at a high-level at all times.
Get It Cold
Coolers, like all things in existence, are subject to the laws of thermodynamics. The first law of thermodynamics states that energy is conserved, but can alter form. At the same time, the principle of entropy (the tendency for things to erode into chaos) is at work, which is expressed in the second law of thermodynamics.
In other words, everything will decline and decay. Ice is subject to entropy and will turn to water, just like your gear will deteriorate if you don’t take proper care of it.
When you consider how to make ice last longer, you must have a certain critical mass of ice in the first place. With only 14 ice cubes in your cooler, you’ll have a warmer temp and therefore the ice will melt faster.
In addition, freeze any items you can before placing in the cooler. Leave your cooler (empty, obviously) outside, in a walk-in cooler, or in the coldest part of your house prior to packing it.
Keep It Shut
Each time you open your cooler, the outside temperature seeps in. If you’ve ever cooked using a crock pot, the same principle applies: each time you open it you affect the internal temperature. In the case of the crock pot, you will lower the cooking temperature slightly and it takes time for the crock pot to regain its original (high) temp.
With a cooler, you are raising the temperature slightly when that lid opens and, depending on how long it stays open, the ice is going to have to “work” (i.e. use energy, or melt) to get everything back to cold.
The cooler is never going to be any colder than when you first dumped two bags of ice into it. As soon as you add drinks and food, the cooler temperature goes up. Each time you open it, the temperature rises, slightly. This is truer, of course, if you are beach camping in Texas than if you are hunting in the Maine woods in fall.
Pack It Correctly
The more stuff you cram in there, the less ice you can put in. The mass of the ice will compete with the mass of your goods, so in general try to keep the ratio to at least half. Your food and drink should take up no more than half the cooler—the other half should be ice.
When it comes to beverages, you can add some “non-chilled” ones later. Again, when adding items later on—the hotter they are, the more they will melt your ice. When considering how to make ice last longer, keep in mind that adding one hot can of beer can have a big impact.
Another tip: pack your food in layers to make sure it is evenly chilled (disregard if using block ice!)
Use Block Ice
Block ice can be difficult to find, and it may not be the best thing for your IceMule pack, but we recommend looking. It lasts longer and is less of a hassle to paw through. We seem to have found more of it in the South and at stores that sell bait. It seems as if those who fish and hunt know how to make ice last longer in a cooler. They buy the right ice.
Keep It Shaded and Insulated
When you can, keep the cooler in a part of your car or campsite that doesn’t get as hot. Although fancy coolers on the market today will still perform well, it’s best to minimize outside heat. This is less of a factor when it’s shut, but when you open the cooler to root around for your lunchmeat, sunlight and heat will penetrate.
If it has to stay in a warm car, insulate your cooler with a sleeping bag or blanket—even if it’s a fancy, high tech cooler.
Make Sure It Seals
Last, sealing ability is a factor in how to make ice last longer in a cooler. Make sure the cooler has seals that do their job. If they are degraded (this doesn’t take long if you live in a hot, dry climate), replace them. On your IceMule cooler, make sure you’re buckling down your cooler each time you close it, to prevent as much warm air from entering as possible.