The Simple Cooler Trick That Keeps Summer Snacks Cold For Hours

The success of a summer outing is often contingent on the coolness of your cooler. After a long day out on the beach or in a park, have you ever reached in for a crisp bottle of water and found a watery ice cube soup instead? We're here to help! Of all the expert tips to help keep your food cold during summer excursions, this one is probably the easiest: just pack it completely full. 

Why does a packed cooler stay cool for longer? Well, according to the second law of thermodynamics, heat will always flow naturally from warmer objects to cooler objects. Likewise, heat will naturally find its way into cooler spaces and warm it up over time. When you think of a half-empty cooler, it's not actually empty–it's full of air. And every time you open the lid, the hot outside air will always come in, displacing the cold air, and melt your ice faster. So essentially, the more free space there is in your cooler, the faster it'll warm up throughout the day.

The solution to this is packing your cooler to the top. This minimizes the amount of air pockets inside, so there's no space for hot air to sneak in. Ultimately, overpacking your cooler is the secret to cold food and drinks all day.

So what exactly should you fill all that extra space with? The smartest thing to use would be frozen water bottles, which act as both heavy-duty ice packs and extra drinks at the end of the day. Using frozen bottles also prevents the soupy water situation that often occurs when you use loose ice. 

Although normal ice cubes work perfectly fine to keep your food cold, keep in mind that smaller chunks of ice melt more quickly than large ones. This brings us to another useful tip: The larger your chunk of ice, the longer it's going to last. If you have freezer space at home, you could even make your own jumbo-sized ice cubes using wide plastic containers.

It's also good to keep the size of your cooler in mind for the number of items you're planning to pack. It's generally recommended to have a 2-to-1 ratio of ice to foods or drinks. So if you plan accordingly, your container will be two-thirds of the way full with just ice. Above all, make sure the whole thing is packed right to the top to minimize the amount of air inside and to maximize the chill vibes.