Iron Flask Water Bottle Review

Overall Score

Last Updated August 19, 2021
  • Ease of Use 70% 70%
  • Durability 60% 60%
  • Seal 80% 80%
  • Maintenance 60% 60%
  • Insulation 90% 90%

Key Takeaways


Budget Friendly Bottle

A budget-conscious and feature packed bottle.


Impressive Insulation

The weight to insulation ratio was stellar.


Hand-washing Required

The bottle is not dishwasher safe but hand washing is easy.

No Sweat

Changeable Tops

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Iron Flask does not carry the notoriety of Yeti or Hydro Flask but our reviewers found it still worthy of consideration after several weeks of testing. The bottle offers an impressive combination of capacity, weight and value. For having stainless steel double walled construction it is relatively light, weighing only three ounces more than the 26oz Yeti Rambler.  At the time of this review, it’s also easier on the wallet, costing half the price of the 26oz Yeti. 

Another unique attribute of the Iron Flask bottle is the color selection: you can pick from an impressive 18 different bottle colors on their website. Several of these color schemes offer a neat gradient effect, starting on the bottom as one solid color and transitioning to a different shade or color further up the bottle. 

Iron Flask appears to be a relatively young company with their website providing little in the way of background on the company or founders [1]. The HydrationReview team values transparency about the founders and origin story but it’s not a deal breaker. A lifetime warranty against manufacturing defects gives the consumer some piece of mind when shopping from a company that is not as established. Our testing revealed the bottle is versatile and well built.

Ease of Use

Iron Flask offers three different tops and replacement straws, each serving a slightly different purpose. The combination of multiple straw options and its reasonable weight render it useful in many different environments. Functionally, the only major downside is that it cannot fit into a cup holder. 

Across many different use cases, the straw top was our all-around favorite; reviewers noticed they were drinking more water at their desk when it only took a flick of the straw to start drinking. The only downside to this strategy is the straw imparts a hint of plastic flavor. But when really thirsty, our reviewers did not mind. There is also a conveniently placed handle on the lid with a spring loaded ring that acts as a carabiner so the user can secure the water bottle to their backpack. We found it to be a practical and sturdy feature. 

The other two lids covered different use cases: one was the traditional screw top and the other had a sipping function for hot beverages. In total, they span all the practical applications for the bottle. 

Reviewers were drawn to this bottle for use in the gym, finding it to be a great fit for long workouts that required constant hydration. For this use case, the specific reviewer chose the straw top for easy access to the water between sets on the squat rack. 

Pro tip: Another favorite use for the bottle was cold weather outings like snow shoeing. One reviewer filled the bottle with lukewarm water before heading out snowshoeing along the Madison River in Montana and was able to stay hydrated despite the dry air and heavy exertion. On past trips this reviewer had brought a plastic bottle and found it was difficult to drink because the water was too cold. Normally, cold water is refreshing but when it’s 8 degrees Fahrenheit, warm water goes down much easier.


Iron Flask held up moderately well when it was dropped onto hard surfaces. During the testing period, after several accidental and not so accidental drops, the bottle sustained one large dent to the bottom of the flask. The dent had scratches revealing the steel bottle beneath the powder coating. Considering the larger capacity of this bottle (making it heavier than other bottles when hitting the ground), we were impressed with the results. The large diameter of the bottle partially compensated for the dent and it would still stand upright after the fall. We don’t think this bottle would fare well after repeated abuse, but our testing didn’t have any catastrophic results. 

Iron Flask next to binoculars and bear spray.

The Iron Flask was an essential piece of gear on a hike in bear country.

Here’s a note from a reviewer related to the Iron Flask’s durability:

“I put this bottle to the test and made sure it was dropped a few times on different surfaces. Overall the denting wasn’t that bad. We should note that even before my planned and unplanned drops of the Iron Flask I noticed that the paint was peeling off a little bit on the edges. This could have been a one-off defect, but this could also be a larger quality issue that buyers should be aware of.”




There were no leaks identified when tested with the straw cap, and the twist on cap performed just as well. The sipping top may require additional attention because those tops are typically prone to leaking, but during testing we encountered no issues. As always though, we advise readers to be extra careful when using a straw cap. Leaving the straw open even a little bit when stowing your bottle in a bag could end up with your belongings getting an unwanted bath. 


The Iron Flask is not dishwasher safe, sadly. If this is a make or break feature, consider the Yeti or Hydro Flask. The wide mouth facilitates hand washing so it will not be too onerous of a task. On the other hand, the straw top is harder to clean and could be problematic if used with flavored liquids. We would suggest the simpler twist off cap if you want to use electrolyte mixes or even coffee. 



The Iron Flask fared well in our temperature tests, only losing 8.5°F over the course of eight hours. We were happy with the results, given that it has less material than many other bottles. It was not the top performer, but is perfectly acceptable for most casual use cases where temperature control is necessary.


1“About Iron Flask: Our Story.” Iron Flask, Accessed 6 Mar. 2021.

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