Thermos Guardian Stainless Hydration Review

The flip cap is becoming more and more prevalent in water bottle design across the board. Stainless steel, plastic, and glass bottles are now often coming with a one-handed button-operated lid. The Thermos Guardian is one such bottle, but unfortunately our least favorite iteration of this design we've tested. The Guardian was not easy to operate and its carrying handle felt bulky and poorly shaped. It did insulate fairly well and didn't impart flavors too much.

Performance Comparison

Ease of Use

This metic is really where the Thermos Guardian falls short. The lid has a push button, a locking mechanism, and a carrying handle, but all of these features felt like they were made from cheap materials that didn't work very well. The lock worked but felt gimmicky. The push-button was sticky and often required a second push to actually open. Finally, the carrying handle doesn't fold flush against the bottle, so it sticks out at a 90-degree angle when not in use, which bothered our testers. On the plus side, it is easy to fill and clean, as its wide mouth accommodates a bottle brush easily. The lid, though complex and clunky, also cleans fairly easily due to its wide spout.

Durability

Overall, this stainless steel option did well in our durability tests. When dropped, the bottle got a few small scuffs and a small indent on the bottom, but beyond that was unscathed. This is typical for a stainless steel, insulated bottle, but we were pleased nonetheless.

When it came to our leak test, though, the Thermos Guardian was a little less impressive. When shaken, even with only water inside, the bottle leaked a few drops out of the flip cap. When left resting on its side filled with colored water, a few drops leaked out onto the paper towel after a few hours. Again, this reaffirmed our lack of confidence in the overall lid design on this one.

Weight

In comparison to its stainless steel peers, the Thermos Guardian is impressive when it comes to weight. Though its capacity is only 24 ounces, the bottle weighs in at 12.7 ounces, giving it a weight-to-volume ratio of 0.53 ounces. This is on the lighter end of the spectrum in the world of vacuum-insulated bottles.

Taste

When we conducted our taste test on the Guardian we were impressed by its easy-to-clean design and its ability to shed flavors. If this bottle has a strong suit, this testing metric would certainly be it. After filling it with drink mix and then washing it with a bottle brush and a tiny bit of soapy water, the Guardian was more or less returned to its original state. Additionally, there were no plastic-y flavors when we took it out of the box initially, adding to its high score in this metric.

Value

This is a very affordable bottle, especially compared to its vacuum-insulated, stainless steel counterparts. The Guardian is on the cheaper side of most of the bottles we tested and it shows. We hate to say it, but this bottle doesn't seem like it was built to last. The flip-cap started to get sticky after only a few days of use and the locking mechanism was prone to get stuck as well.

Conclusion

Though it's affordable, the Thermos Guardian was not our favorite bottle in the line-up. Its feature set left a lot to be desired — the buttons were clunky and the carrying handle was ill-sized and bulky. It is easy to drink from the spout, but the button to open the flip cap didn't work very well. We think most folks will be better served looking for a different bottle with fewer gimmicks and more simple functionality.