Hydro Flasks: 33 Most Commonly Asked Questions Answered

Launched in 2009, Hydro Flasks are the gift that keeps on giving.

These flasks not only maintain your drink’s temperature for longer, but they are also quite stylish. This makes them appealing to Millenials and Gen Zs alike. In fact, they have become somewhat of a Gen Z craze.

But if you’ve never used these flasks before, it is normal to have a lot of questions about them.

So to help you out, we have decided to answer some of the most commonly asked questions about Hydro Flasks.

Can you put your Hydro Flask in the dishwasher?

While some Hydro Flasks are dishwasher-safe, others are not. Particularly, powder-coated flasks manufactured after the year 2020 are dishwasher safe while those manufactured before aren’t. This is because the older models are more fragile than the new ones and therefore can’t handle being washed in a dishwasher.

Interestingly, when it comes to the lids of Hydro Flasks, you have to deal with the same problem – some of them are dishwasher-safe while others aren’t. The lids that are dishwasher safe are the hydro flip lid, the wide mouth flex slip cap, and the wide mouth straw lid.

On the other hand, the narrow loop cap, standard loop cap, standard mouth flex cap, standard mouth sports cap, wide mouth flex cap, wide mouth flat cap, and stainless steel flat cap aren’t dishwasher safe.

What happens if you put your Hydro Flask in the dishwasher?

While dishwasher-safe Hydro Flasks will be fine throughout the dishwashing cycle, the rest won’t. For one, the flask’s vacuum seal can break, allowing air to fill the gap between its inner and outer walls. Ultimately, this makes the flask lose its ability to keep your drinks warm/cold. Beyond that, it can make your flask fade and lose its color.

How do I know if my Hydro Flask is dishwasher-safe?

Whenever you buy a new Hydro Flask, check the printed materials that come with it for cleaning and care instructions. This is where they usually indicate whether your flask is dishwasher-safe or not.

How to properly clean a Hydro Flask?

No matter which type of Hydro Flask you own, you can easily hand wash it using warm soapy water.

While you can use a brush to clean the inside of the flask, a soft sponge/cloth is enough to clean the outside.

How often should I wash my Hydro Flask?

Ideally, you should wash your Hydro Flask in warm soapy water one to two times a week.

Beyond that, you should wash it as soon as you finish using it to drink a beverage like milk, tea, juice, or wine.

Can you put soda in a Hydro Flask?

While some people claim that putting soda in a Hydro Flask can make it have a metallic taste, there is no evidence to suggest this.

While soda is acidic, it is not as acidic enough to destroy or dissolve the stainless steel layer inside Hydro Flasks.

Can you put iced tea in a Hydro Flask?

Yes, you can put iced tea in a Hydro Flask.

Can I put carbonated drinks in a Hydro Flask?

Yes, you can put carbonated drinks in your Hydro Flask. Since its cap has a silicone seal, it can keep your drink carbonated for long periods.

Can you put flavored water in a hydro flask?

Yes, you can put flavored water in a Hydro Flask.

Can I put lemon water in my Hydro Flask?

While lemon water is acidic, it doesn’t affect the stainless steel inner layer of a Hydro Flask. However, some people claim that lemon water makes Hydro Flasks emit a metallic taste.

Can you put alcohol in a Hydro Flask?

Yes, you can put alcohol in a Hydro Flask. There’s even a Hydro Flask that’s been specifically designed for the storage of alcohol – the Growler. This type of flask will not only keep your beer cold for hours on end but also not leech any of the bottle’s chemicals.

Can you put wine in a Hydro Flask?

Yes, you can put wine in a Hydro Flask – a Hydro Flask can accommodate an entire bottle of wine and keep it at the same temperature for at least four hours.

Can I put champagne in a Hydro Flask?

Yes, you can put champagne in Hydro Flasks – all kinds of sparkling wine can be put in these flasks.

Can you keep milk in a Hydro Flask?

Yes, you can put milk in a Hydro Flask – this type of flask can keep milk for hours. Ultimately, the period that a Hydro Flask can keep your milk is dependent on the starting temperature of the milk, the temperature of the environment, and whether or not any ice cubes/sticks have been added to the milk. For instance, if you add reusable ice packs to your milk, it could stay cold for up to 24 hours.

Is it OK to put hot coffee in a Hydro Flask?

Since hot coffee isn’t that acidic, it can be put in a Hydro Flask without damaging it in any way. In fact, it’s not even as acidic as soda. Beyond that, it’s worth noting that most coffee machines are made of stainless steel – the same material that makes up the inner lining of Hydro Flasks.

Can I put soup in my Hydro Flask?

Hydro Flasks are one of the best containers to hold your soup in. Since they are tightly sealed, they can keep your soup hot for long periods.

Can you put boiling water in a Hydro Flask?

Yes, you can put boiling water in your Hydro Flask. In fact, these flasks can keep your water hot for at least 6 to 12 hours. So whether you need water for noodles or coffee, these flasks are a good way to store your water.

Can you put hot chocolate or tea in a Hydro Flask?

Yes, you can put hot tea and chocolate in your Hydro Flask. These flasks can even keep your hot beverages hot for 12 hours.

What should you not put in a Hydro Flask?

If there is one thing that should never get anywhere near your Hydro Flask, it is bleach/chlorine. This chemical destroys the inner stainless steel layer of your flask and causes it to rust.

How long does a Hydro flask keep things hot?

A Hydro Flask can keep things hot for up to 12 hours.

How long does a Hydro Flask keep things cold?

A Hydro Flask can keep its contents cold for up to 24 hours.

How is a Hydro Flask insulated?

Hydro Flask uses a unique double-walled vacuum insulation technology called TempShieldTM – their sealing process is unique and their ovens proprietary. All this works together to ensure maximum insulation.

Why is my Hydro Flask not keeping water cold/hot?

The most likely reason that your Hydro Flask isn’t keeping your water hot or cold is that its vacuum seal is compromised, letting air in. Unfortunately, this is not something that can be fixed.

However, other factors could cause this heat gain or loss as well. They include:

  • Leaving the flask’s lid open – this lets air into your flask making heat loss or gain faster.
  • If you’re storing cold water and putting enough ice/reusable ice packs – the more of these cubes/packs you add, the longer your water will stay cold.

Can you put Hydro Flask in the fridge?

Yes, you can put your Hydro Flask in a fridge – nothing bad will happen to it.

But if you want the water inside the flask to be cold, you’ll have to remove its lid. And even then, the process will take longer than it would if you just used an ordinary container/bottle.

Can you put Hydro Flask in the freezer?

While nothing bad will happen if you put your Hydro Flask in your freezer, it is pointless. It won’t get your water to ice-cold temperatures.

If you want your water to freeze, you’re better off using an ordinary bottle.

Does Hydro Flask warranty cover dents?

A Hydro Flask’s warranty covers manufacturing defects and any dents it gets during shipping. But it doesn’t cover any dents that result from you dropping or using the flask.

Why does my Hydro Flask smell weird?

If your Hydro Flask emits a bad smell, it could be a sign of bacteria or mold buildup. This is particularly an issue if you don’t clean it well or leave it out to dry properly.

Alternatively, the smell could be from a beverage you had put in the flask.

How do you get the smell out of a Hydro Flask?

The best way to get the smell out of a Hydro Flask is to deeply clean it. For one, you can start by washing it in warm soapy water. If the smell persists, you can fill the flask with boiling water, cover it with its lid, and let it sit for 6 to 12 hours.

Beyond that, you can use lemon water or vinegar to absorb the smell.

How do you sterilize a Hydro Flask?

To sterilize your Hydro Flask, soak it in vinegar and scrub its interior with a baking powder paste.

Start by pouring some vinegar into the flask, close it, shake it to ensure the liquid spreads all over the inner surface, and let it sit for a bit. Afterward, soak the lid in vinegar as well and make a paste using baking powder and water/vinegar.

You can then use the paste with a brush to scrub the flask.

Alternatively, you could use bottle bright tablets.

All you have to do is put the tablets in your Hydro Flask, add some water, and let them fizz out and dissolve in the liquid. The resulting solution will clean out the flask for you.

Afterward, you can just remove the residue with a bottle brush.

How do you get soap taste out of Hydro Flask?

One of the best ways to get soap taste out of your Hydro Flask or other bottles is by soaking them in vinegar.

Do Hydro Flasks rust?

Since Hydro Flasks are made of stainless steel, they are rust-resistant. The only way this can happen is if you use harsh chemicals like bleach or chlorine on your flask.

Can you boil a Hydro Flask?

No, you can’t boil or cook anything in a Hydro Flask. Because of the double-walled vacuum these flasks have, they have a hard time conducting heat from the outside to the inside. As such, cooking or boiling water in them would be pointless.

Is Hydro Flask better than Yeti?

While Hydro Flasks are more popular than Yetis, they are not always better than them. Each one has its strengths and weaknesses.

When it comes to sheer size though, Hydro Flasks are unmatched, offering several size options for you. Also, these flasks come with a lifetime warranty while Yetis only come with a 5-year one. And to sweeten the pot, Hydro Flasks are more affordable than Yeti ramblers.

However, Yeti’s caps have something that Hydro Flasks’ caps don’t – 3-finger grasp technology. This makes them way firmer.

Another thing that Yeti ramblers have going for them is their solid handles – Hydro Flasks’ strap-style ones aren’t as strong. And while both these brands of water bottles are durable, Yetis get fewer dents when dropped compared to Hydro Flasks.

Ultimately, the better bottle for you is the one that best suits your needs. So before you get any of these flasks, you need to take the time to do the necessary research.

So, check out these articles on S’well bottles, Contigo reusable bottles, and Klean Kanteen water bottles for some inspiration.


  1. cleaning stainless insulated cups, flasks is a major pain, we use ours for black tea and it stains terribly, baking soda/vinegar do not do the job only those harsh dishwasher tablets can get them clean and that is an expensive solution.

  2. I’m seeing black stuff on the red silicone insert and I know it’s not black mold because i’ve seen it for awhile and haven’t had any negative symptoms. I believe it is residue from the black lid staining the red insert and sometimes the tip of my straw has some black coloration. I’ve tried hand washing, scrubbing, and soaking the insert in warm soapy water but there are still black marks. Can I boil the silicone insert to sterilize it?

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