Have you ever wondered how, exactly, the Polar Bottle team assures our products work as well as they do? To figure it out, we sat down with Polar Bottle engineer Nicholas Pappianou to pick his brain about the product testing that takes up much of his time during the hot spring and summer months between April and September.

At Polar Bottle, Nick explained, we test our entire bottle line outside under the hot Colorado sun during peak heat summer hours. Boulder, Colorado, where our office and testing facilities are located, lies at 5,430 feet above sea level, meaning the sun’s rays are stronger here than in other parts of the country.

If the bottles were tested at sea level, for example, results would be very different and the water would likely take longer to heat. By testing outside at a high altitude we are able to see how our products work under extreme conditions, helping us guarantee that our bottles’ thermal technology will hold up no  matter how our customers use them.


To test insulation capabilities, the Polar Bottle engineer team sets up a large ice bath with water at a temperature between 32.5°F and 33.5°F.

When testing a Polar Bottle Sport water bottle, the cold water is then transferred to the bottle using a filter so that no ice crystals get into the water. Although most of our customers tell us that they use ice in their sport water bottles, during testing we avoid ice so that the water temperature stays consistent and so we can better understand how the bottle’s insulation technology performs on its own without added cooling.

“With the Polar Bottle Sport, we expect that it might be filled with only cold water or that it will be taken on long rides when the ice will melt,” Nick said. “So we want to know how the bottle performs once the ice is gone.”

When testing how our products compare to other reusable water bottles on the market, the same procedure is followed to fill competitor products.

Once filled, the Polar Bottle water bottles and the competitor water bottles are placed in direct sunlight on the same block of concrete. From there, engineers measure the temperature of the concrete, the outside temperature and the water temperature at regular intervals throughout the day. To help assure accuracy, engineers compare the outside temperatures recorded to weather data from the National Oceanic and Atmospheric Administration.

Engineers will test the bottle’s thermal capabilities in a variety of ways. For example, they might test to see how long it takes for the water in the bottles to reach a certain temperature — usually between 70°F and 90°F. Typically, however, engineers test how long it took for the water in the bottle to reach equilibrium. Equilibrium is the point at which the water in the bottle is the same temperature as the outside air, whether that is 90°F or 60°F.

Along with conducting tests comparing Polar Bottle products to our competitors, engineers also test how different Polar Bottle bottle designs and colors compare to one another.

Lighter colored foil bags, for example, tend to perform better than darker colored bags. The older bottle designs also perform differently than newer designs.

“We will test about three years worth of Polar Bottle designs,” Nick said. “By constantly comparing our bottles to one another we can continue to improve our products’ thermal characteristics.”

For example, Nick explained, when Polar Bottle updated its bottle design in 2006 with a sleeker body design and colored foil liners, the thickness of the plastic decreased and the bottle lost a small amount of insulation. To make up for this, Nick and the rest of the engineering team adjusted the shape of the dimples lining the inner plastic bottle. By rounding the dimples, making them more of a dome shape rather than flat, they were able to add an air gap that limited the conduction between the two insulating layers — keeping the water cooler longer.


On average, on a hot summer day — 90°F or higher — water without ice in a Polar Bottle Sport water bottle takes about two hours to reach equilibrium.
“This is about two and a half to three times longer than a non- insulated, single-wall water bottle,” Nick said.

Despite these impressive results, Nick says he and the rest of the team continue to work every day to improve the Polar Bottle water bottle line.

“We are always making improvements — whether that means making the plastic in the Polar Bottle sport easier to squeeze or tweaking the design elements in the lifestyle bottles,” Nick said. “We were the original insulated water bottle on the market and we want to make sure we honor that legacy by ensuring that we are also the best.”