Iron Flask vs Hydro Flask

Wheather you’re spending days or weeks hiking and camping or just out for a run or cycle, having a quality, well-made water bottle is vital. Not only do these simple but extremely well made products keep drinks cold during summer outings, but they also keep hot beverages hot for hours, and this can come in very handy during winter hikes. But, which do you choose Iron Flask vs Hydro Flask

Besides being capable of retaining the temperature of hot and cold drinks, well-made flask bottles are also very durable. Those who opt for a heavy-duty model will be able to use it for the years to come, as such water bottles do not get damaged even if they’re dropped on rocky terrain.

Instead of choosing to go with a cheap product of this type, check out my detailed analysis of the market’s two best insulated water bottles – Iron Flask and Hydro Flask. I’ll take a closer look at their features, check out how they compare to one another, and help you determine which one of them suits your needs the best. This post is part of my series of best hiking water bottles.

Hydro Flask vs Iron Flask – The Main Differences

These are the primary differences between the two of the market’s best insulated water bottles:

  • Iron Flask comes without a leak-proof cap, unlike Hydro Flask.
  • Iron Flask is available in more sizes, while Hydro Flask has a somewhat limited capacity range.
  • Hydro Flask is equipped with one lid, while its rival comes with three lids.
  • Hydro Flask is a dishwasher-safe water bottle. Its rival, on the other hand, requires manual washing.

Hydro Flask vs Iron Flask – A Detailed Comparison

As is the case with most products of this type currently on the market, these two stainless steel water bottles have a lot in common. For that matter, the first thing I’ll do is check out what makes these water bottles similar:

Powder Coated

The exteriors of both Iron Flask and Hydro Flask sport a special powder coating.

This translates to increased durability. If any of these two water bottles fall out of your hand, the impact of the drop will be absorbed fairly well. Furthermore, the fact that these bottles are powder-coated brings yet another advantage – a better grip. This feature can be of extreme importance to all those planning to use these water bottles for activities such as climbing or trail running.

This special finish allows these popular flasks to be available in a vast assortment of different colors as well. The Iron Flask, for example, can be obtained in 24 different colors, ranging from fire red to graphite to aquamarine. The Hydro Flask, on the other hand, is available in 8 colors less (so, 16 in total). Some of these include watermelon, olive, sunflower, and others.

Stainless Steel

One of the best things about Iron Flask and its main rival is that they’re both stainless steel water bottles. This brings several advantages into play.

First of all, the stainless steel construction of these products greatly increases their durability – both Iron Flask and Hydro Flask are incredibly sturdy. A stainless steel bottle successfully absorbs impacts for as long as it isn’t dropped from a high height.

Another important advantage is that these bottles are made out of a special kind of stainless steel, and that’s 18/8 pro-grade stainless steel. What does this mean? It means that they’re not only very rugged but also very easy to clean and can keep the taste of your hot or cold drinks as pure as possible. That being said, the Iron Flask requires manual washing (use soapy, warm water) whereas the Hydro Flask can be washed in a standard dishwasher, i.e. it’s a dishwasher-safe product.

I should also mention that both of these bottles are 100% BPA-free. And when a stainless steel water bottle is 100% BPA-free, it is better for the environment and much safer to use. In the last decade, there has been great pressure on brands such as Iron Flask, Hydro Flask, Klean Kanteen, Yeti, and Sendestar to remove dangerous chemicals from their products, and it’s good to see them actually doing that.

Heat Retention

When you’re hiking in winter, you want to keep your drinks hot. You want to keep your tea, coffee, or soup hot so that you can enjoy a warm drink whenever you want during your backcountry adventure. An extremely important feature of these insulated water bottles is that they can keep liquids hot, no matter where you are.

As mentioned above, this can be very useful during the year’s colder months. While it’s true that you’ll still need to drink cold water to keep yourself hydrated, drinking hot beverages while hunting or trekking makes the experience more enjoyable.

On one hand, Iron Flask can keep one’s drinks hot for the duration of 12 hours. In my opinion, an insulated water bottle that can keep your drinks hot for 12 hours is a very good bottle. If you put some coffee or tea into your Iron Flask, the model will keep your drinks warm for half a day.

On the other hand, Hydro Flask can also keep drinks hot when you’re exploring the backcountry in cold winter months. Although the manufacturer states that this double-walled water bottle can keep your drink hot for about 12 hours, some people report that the model is not as good as its main rival in this regard. In any case, Hydro Flask features double-wall vacuum insulation, and therefore can and will keep your beverages hot throughout the day, and is a great choice for short outdoor excursions.

Keeping Liquids Cold

Just like the bottles made by Yeti or Klean Kanteen, and other manufacturers, both of these products can keep drinks hot and cold. As you can already guess, this is of vital importance when it comes to outdooring activities taking place during hot summer days. A sip of warm water is the last thing you need when you’re hiking miles upon miles of rugged terrain at 100°F.

The Iron Flask is capable of keeping one’s drink cold for 24 hours. Having a bottle that keeps drinks cold for 24 hours can be immensely useful when you’re embarking on an extensive outdoor adventure in the summer. Once you fill the bottle up, you don’t have to worry about anything – you’ll have access to ice-cold water all day long.

What about Hydro Flask? Just like its rival, this water bottle can keep liquids cold for a good amount of time. Just like the Iron Flask, it can keep drinks cold for 24 hours. So, in other words, if you fill the Hydro Flask with water in the morning, the bottle will keep that same water cold all the way until the evening and even longer. However, I should point out that some users have reported inconsistencies in regards to this – some of them say that the bottle cannot keep water cold for so long.

Iron Flask – The Unique Features

Iron Flask


Of course, there are some differences between these two products. One of the most important features that are unique to Iron Flask is the fact that it comes with three lids. Its rival, on the other hand, has just one lid.

While it’s possible to buy an additional lid or two for your Hydro Flask, these come at a cost. This is what turns the Iron Flask into the winner in this department, as it doesn’t have just one lid but comes equipped with three lids. These are the stainless steel lid, the flip lid, and the carabiner straw lid. So, it’s pretty safe to say that there are several options available when it comes to drinking out of this insulated water bottle.

Another important feature about this water bottle is that it’s available in more sizes than its rival. You can buy this bottle in a 64-ounce, 40-ounce, 32-ounce, 22-ounce, 18-ounce, and 14-ounce variant. This diverse lineup of bottle sizes allows potential buyers to purchase a model whose dimensions suit their specific needs.

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Hydro Flask – The Unique Features

Iron Flask vs Thermo Flask

Some features are unique to Hydro Flask. The most important one of them is the fact that this double-walled vacuum-insulated water bottle comes equipped with a leak-proof cap.

However, the fact that this model comes with a leak-proof cap doesn’t mean that its manufacturer has decided to equip it with one because it’s prone to leaking. The primary purpose of the leak-proof cap is just to decrease the number of potential leakages and spills. I have also compared Thermoflask and Hydro Flask here.

Amidst these comparisons, enthusiasts often explore other matchups like the Hydro Flask and Hydrapeak face-off, broadening the spectrum of choices and features for consumers.

Another advantage that the Hydro Flask has over its rival is that it’s a dishwasher-safe water bottle. It is, therefore, extremely easy to clean – you just have to put it inside your dishwasher and that’s it. No need for a hand wash! However, the model is available in only three sizes, with the 24-ounce bottle being the most popular choice (the other two options are 18oz and 21oz).

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Iron Flask vs Hydro Flask – The Price

There is one specific department in which these two vacuum-insulated bottles diverge quite a bit, and that’s the price department. If you’re looking to save some money, your best bet is to go with the Iron Flask, since it comes at a lower price than its rival. And while both models can be obtained in several different sizes, the Iron Flask offers more options in that area, as I’ve already mentioned.

The Iron Flask is available in the following sizes:

  • 64oz
  • 40oz
  • 32oz
  • 22oz
  • 18oz
  • 14oz

The Hydro Flask, on the other hand, is available in only three sizes, and these are:

  • 24oz
  • 21oz
  • 18oz

Are you on a budget? If that’s the case, go with the Iron Flask – it is more affordable. What’s more, it is available in three additional sizes when compared to its rival. While the cost between these two stainless steel bottles isn’t huge, it is certainly noticeable and can be a deal-breaker for some people.

If you want to see what other budget-friendly options are out there, check out my EcoVessel vs Hydro Flask comparison as well.

Hydro Flask vs Iron Flask – The Pros & Cons

Iron Flask Pros

  • Affordable – a better option if you’re looking to save money
  • Protects the temperature with its double-wall vacuum insulation
  • It can keep water and other liquids cold for 24 hours and hot for 12 hours
  • Durable stainless steel, powder-coated, BPA-free construction
  • Available in 6 sizes and 24 different colors
  • Comes equipped with three different lids, including a straw lid

Iron Flask Cons

  • Does not come with a leak-proof cap
  • It’s not dishwasher-safe

Hydro Flask Pros

  • As durable as its rival – powder-coated, BPA-free, stainless steel build
  • Protects the temperature with its double-wall vacuum insulation
  • Keeps your drink ice cold for 24 hours and hot for twelve hours
  • A Dishwasher-safe water bottle – no need for a hand wash

Hydro Flask Cons

  • Limited size and color range
  • The price is higher than that of the Iron Flask
  • Only one (standard mouth) lid

Hydro Flask vs Iron Flask – The Alternatives

Yeti Rambler Reusable Water Bottle

Aquifer blue Yeti rambler

If none of the two models I’ve analyzed above looks like the best water bottle for your needs, make sure to check out Yeti’s immensely popular Rambler bottle.

I have compared Yeti to the Hydro Flask before and came to the conclusion that Yeti Rambler is a (slightly) better choice. As Yeti is the market leader and often more expensive I have also written about alternatives to Yeti. This insulated water bottle is equipped with a range of innovative features that allow it to keep beverages hot or cold for a long period of time. The model is available in 12 different colors and is dishwasher-safe.

Rambler’s 18/8 stainless steel leak-proof construction turns it into one of the most durable products of this type currently available on the market. Furthermore, it provides the user with a good grip thanks to the DuraCoat coating on its exterior, which also protects the bottle from cracking, peeling, and fading. Finally, those who don’t like wide-mouth bottle openings will be very pleased to find the so-called “chug cap” on this model.

Price-wise, the Rambler is closer to the Hydro Flask. In other words, it’s among the market’s more expensive products of this type, but its price is certainly justified by its phenomenal build quality as well as its capability to keep one’s drink ice cold or pleasantly warm for hours.

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Sendestar Wide Mouth Bottle

Sendestar bottle

Here’s another great alternative to the two bottles I’ve compared above – Sendestar Stainless Steel Bottle. This particular model is available in the following sizes – 64oz, 40oz, 24oz, and 12oz.

While not important, one of the best things about this bottle is its eye-catching design. It is available in over 40 attractive colors and each version looks both trendy and minimalist, with some variants looking very similar to the popular Klean Kanteen flasks. If the look of your hiking equipment is important to you, go with this bottle – you won’t be disappointed with its design.

The durability of this wide-mouth bottle is ensured by its rugged construction, with 18/8 stainless steel being the main material used in its manufacture. Sendestar is capable of keeping your hot drink warm for about 12 hours, but it can also keep your water and other beverages as cold as ice for up to 24 hours. This turns it into an ideal choice for both longer camping adventures and shorter day hikes.

The Sendestar bottle comes accompanied by two lids. These lids are the flex cap lid and the spout lid, and they can be switched at any time. The flex cap lid is ideal for walking, running, and hiking, while the spout lid turns this bottle into a great choice for beach and camping trips. The wide-mouth opening of this bottle, on the other hand, provides plenty of space for ice cubes and makes cleaning extremely easy.

Overall, the Sendestar bottle is very well-made and comes at a pretty affordable price, too. It is, in my opinion, a great alternative to the two bottles I’ve compared in this article.

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Frequently Asked Questions About Iron Flask & Hydro Flask

How easy is it to clean these bottles?

It’s very easy. The stainless steel build of these flasks means that cleaning them is a hassle-free process. However, I should point out that the Iron Flask needs to be washed manually, as it is not dishwasher-safe like its rival.

Are these flasks available in different colors?

Yes, they are. Each bottle can be obtained in a very wide variety of colors, especially the Iron Flask, which is available in 24 different colors. Its rival, on the other hand, is available in 16 different colors.

Is each bottle covered by a warranty?

Yes, both of the bottles I’ve analyzed in this article come accompanied by warranty deals. In fact, both manufacturers are quite generous in this department, since both the Iron Flask and the Hydro Flask come accompanied by lifetime warranties.

Are these flasks capable of keeping beverages warm?

Yes, they are, and the reason behind this is the fact that they both feature double-walled, vacuum-sealed insulation. This allows them to keep various beverages warm (but also cold) for long periods of time. In these, liquids such as coffee or tea can stay warm for up to 12 hours. Pretty impressive heat retention, wouldn’t you say?

How long can these bottles keep the water cold?

Both of the flasks I compared above are advertised by their manufacturers as being capable of keeping liquids cool for the duration of one whole day (24 hours). Both models are pretty good at achieving this and can manage to do so even in humid conditions, which is seriously impressive. However, do not expect miracles if you’re planning to use them in extremely hot climates.

Are these flasks safe to use?

Yes, they are safe to use. Like I’ve mentioned a few times throughout the article, both models are BPA-free. The pervasiveness of materials that contain BPA (Bisphenol A) has been raising major concerns in the last decade, which is why most manufacturers of hiking bottles (and other products) now design, manufacture, and sell BPA-free products.

Hydro Flask vs Iron Flask – The Verdict

So, which one of these two water bottles is actually the best? Is one really better than the other? Or are they equally good?

As far as I’m concerned, both the Hydro Flask and the Iron Flask are very good at what they do. As I’ve already mentioned a couple of times throughout the article, these double-walled bottles actually have a lot in common. Both are very good at retaining the temperature of your hot drinks, but also at keeping your water cold for hours on end. These characteristics turn them into incredibly useful pieces of trekking equipment, especially for those who often hike in very cold or very hot climates. Furthermore, both models are constructed very similarly – they are made out of stainless steel, have powder coating on their exteriors, and provide their users with an easy grip.

But if I have to choose only one model as the winner of this comparison, that would be Iron Flask, but not by a long shot. There are a couple of things that made us choose Iron Flask as the victor, with its (more affordable price) definitely being one of those things.

While it’s true that skimping on the price is rarely a wise decision (especially if it means paying slightly more for a product that is superior in all departments), I think that picking the cheaper option is the way to go in this particular case. If I take a good, thorough look at all of the features possessed by the Iron Flask, and then compare its rival, the Hydro Flask, I can see that the former option offers similar quality for less money.

Another important advantage that Iron Flask has over Hydro Flask is the fact that it comes accompanied by three instead of just one lid. They’re a part of the package and do not have to be bought separately like in the case of Hydro Flask.

In conclusion, both models are very well-made, practical, and even eye-catching, but Iron Flask is the better option out of the two. It offers the same quality as its rival but also some extras, and is also cheaper and available in more sizes. It’s the perfect choice for both short and long backcountry escapades. Check out our Iron Flask vs Yeti comparison and our Simple Modern vs Iron Flask comparison as well.

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