The difference between a good cooler and a great one isn’t add-ons like cup holders and telescoping handles. The decisive element is much more fundamental: air.
How We Tested
The first modern cooler, trademarked in 1953 by Richard Laramy of Joliet, Illinois, as a “portable ice chest,” was a simple insulated box. Nowadays, coolers are part of just about every American household—but they come in all shapes, sizes, and materials. Bells and whistles range from wheels and telescoping handles to removable dividers and cup holders, and many are made from collapsible fabrics that allow the unit to fold up as small as a gym bag.
Modern innovations aside, we wanted to know how effectively these coolers serve the bottom line: keeping food and drinks cold and securely contained when being hauled to outdoor activities. We surveyed the marketplace and tested five models in varying styles, sizes, and prices, including soft-sided totes, a hard plastic tub, and a $4 Styrofoam box from the supermarket.
The Big Chill
At the very least, a cooler should keep its contents as cold as they were when they went into the box for several hours on a hot day. But could any of these coolers take it one step further and cool down items that were not perfectly chilled to begin with? We loaded up each model with 45-degree sodas (by most people’s standards they weren’t yet cool enough to drink) and ice packs (1 pound for every 2 quarts of cooler capacity, per the manufacturers’ instructions) and placed them in a stuffy room that we cranked to 95 degrees. We cracked open a can from each cooler every hour for four hours and stuck an instant-read thermometer into the liquid. The first good piece of news was that every model—even the cheap foam box—maintained the temperature of the sodas for the full four hours. Even more impressive, two models exceeded our expectations and actually dropped the sodas to a colder temperature.
We were intrigued: A cooler that can act like a refrigerator wasn’t a requirement for us, but it was an appealing feature. Curious why a couple of models had this ability, we looked closer to see how manufacturers were insulating their products. As it turns out, all coolers in our lineup—whether hard- or soft-sided—are made from the polystyrene foam known as Styrofoam. This plastic is widely used for insulation because it’s porous and, therefore, slows the transfer of heat. But with the exception of a $4 cooler, that foam was just one component of insulation. Every other manufacturer used additional materials or design features to improve its product’s performance.
The most effective feature we came across was a layer of plastic lining on the interior of one of the models, which created an insulating air pocket between the cooler’s interior and the foam. Gases like air make very good insulators because they contain relatively few molecules, hence they conduct heat poorly. That explained why this was the only model to not only keep the sodas cool, but to actually chill them to an optimal 40 degrees. (The other model to drop the sodas’ temperature only brought them down to 42 degrees.) What’s more, this impressive cooler had a small hatch sewn into its zip top that allowed us to grab a soda without opening the entire box, thereby keeping the release of cool air to a minimum.
That last point got us thinking about a cooler’s other functions. Besides a beverage chiller, we wanted a container roomy enough to accommodate a weekend’s worth of groceries, but not a bear to move when full or a hog that consumed lots of floor space when not in use.
Storage-wise, two coolers had the large capacities, but it was their flexible fabric walls that gave them, as well as the smaller collapsible model, a real advantage. Not only did these coolers fold down like a duffle bag, but their sides were flexible enough to house multiple bags of groceries.
Meanwhile, one rigid model was about half as roomy as the largest coolers. When it couldn’t accommodate all of the cold-storage goods, we had to perform triage—and only a whole chicken, 1 pound of bacon, and a package of ground beef made the cut.
Most of the soft-sided coolers fared well in the durability test, too. When we tipped them off the tailgate of a station wagon, their zip tops prevented them from bursting open and hurling their contents onto the pavement as one model did, and they didn’t suffer any permanent structural damage. The one soft-sided model failed this test—a peek inside after the tumble revealed a split-open hummus container and a few broken eggs.
The ideal cooler should also clean up odor- and stain-free without a lot of scrubbing. Of the fabric models, only one passed the cleanup tests with flying colors, thanks to its smooth sides and antimicrobial material. When we left fresh cod fillets in each cooler for a weekend and then scrubbed them with hot soapy water, baking soda, and cleaning wipes, the fishy aroma stubbornly clung to the other fabric coolers. Meanwhile, spilled milk dyed green with food coloring mopped up easily from one smooth, hard-sided model, which also features a handy spout for draining liquid.
By the end of testing, we decided that one model was a cooler we’d be happy to take anywhere. Its large fabric-covered frame was lightweight and durable, and its interior plastic lining added an extra layer of insulation. Plus, it rolls on small wheels, pulls along with a telescoping handle, and collapses to the size of a gym bag.
We filled each model with partially chilled sodas and ice packs (1 pound per 2 quarts cooler capacity, per manufacturer instructions) and placed them in a 95-degree room. We checked the temperature inside one can from each model every hour for four hours, giving the highest marks to the coolers that maintained—or even dropped—the sodas’ starting temperatures.
We looked for vessels that were sturdy but not heavy or awkward to move when full. Wheels and handles were plusses.
The sodas we placed in the coolers were less-than-optimally chilled (45 degrees). We gave the highest marks to coolers that were able to drop their temperatures closer to 39 to 40 degrees.
We dropped each cooler from a car tailgate to make sure that it could take a good amount of wear and tear. Models that suffered permanent damage were downgraded.
We dyed milk with green food coloring and spilled a small amount inside each model to test how difficult it was to mop up the mess. We also left fresh cod fillets in the coolers over a weekend and scrubbed the vessels with soap and water, baking soda, and cleaning wipes to test odor retention.
We tested five coolers in a variety of styles, materials, and price points. All models were purchased online.