Hydro Flask bottles are designed to hold iced cold water and drinks for 24+ hours at a time. So what's the deal with putting your Hydro Flask in the freezer?
Why cant you freeze a Hydro Flask? Why do Hydro Flask (and other brands) advise against putting your insulated bottles in the freezer? What would happen if you were to put your Hydro Flask in the freezer?
I have often put my Hydro Flask in the fridge in order to keep my drink cold overnight, but I have thought it could be good to put in the freezer and pre-chill before I fill it up with beer for a beach day down the coast. So I wanted to see if I could just freeze my Hydro Flask the night before and if not, why not?
Hydro Flask say in their care instructions “You shouldn't put your Hydro Flask in the freezer”. Well my curious mind wanted to know why so I did some research and here's what I found:
The reason you can't freeze your Hydro Flask bottle is that as liquid cools it expands in all directions. The expansion can cause the stainless steel walls of the Hydro Flask to deform and can sometimes also break the vacuum seal. If this happens your Hydro Flask will no longer insulate properly.
It's completely possible that you could put your Hydro Flask in the freezer without any issues, but there is definitely a risk of damaging it and if you do damage it or break the vacuum seal by putting it in the freezer it won't be covered under warranty as the care instructions specifically say not to do this.
Why Does Hydro Flask Say Not To Freeze Your Bottle?
I wished Hydro Flask didn't just tell us not to freeze our bottles but they actually told us why.
On their Product Care Page they say:
Put your Hydro Flask in the freezer: Due to the double wall vacuum insulation, the water inside will be protected from the temperature inside the freezer and won’t freeze. If you want ice cold water, put some ice cubes inside your flask and notice how long it takes them to melt!
I don't know about you but to me this doesn't give a good enough reason.
Yes the insulation will protect the contents inside from the cold of the freezer…for a time. But eventually the cold will get in and freeze the contents of your bottle. If you leave the lid off it'll happen even faster.
This doesn't mention anything about why it might break your Hydro Flask or what the problem is with putting it in the freezer.
However, I was able to find this statement from competing brand Contigo where they give a solid reason about not putting their insulated products in the freezer.
On this article about the topic they state:
When liquids freeze, they expand and take up more space. As the liquid freezes and expands, it can cause your water bottle or travel mug to become deformed and misshapen.
Even worse, the expanding liquid might break the welds and seals holding your water bottle together. If you place a stainless steel water bottle in a freezer, you might unintentionally and up damaging the vacuum seal, causing it to lose its insulating properties and not keep your water cold for as long. Ironic, right?
What Do Others Say About Freezing Your Hydro Flask?
Because Hydro Flask don't offer much information about freezing their bottles I wanted to do some more research to see if anyone else out their has frozen their Hydro Flask and what the results were.
I found this reddit thread where someone claimed to regularly put an EMPTY Hydro Flask in the freezer overnight without issues:
I have a 21oz standard mouth that I've been putting in the freezer (empty) overnight to pre-chill without any problems. Been doing it for a couple of years.
Or this person on reddit who managed to freeze water in their Hydro Flask:
So I thought it was a good idea to put my hydro flask in the freezer when it had water in it. My freezer is set to -2 degrees Fahrenheit if that helps. I let it sit there over night and now it’s literally half a hydroflask with ice in it.
Basically, there isn't much online about freezing your Hydro Flask. But it seems that it would be fine if it was empty or put in the freezer to keep something already frozen cold. But freezing things inside the bottle could potentially damage it.
I did find this amazon post where a lady named Christine said that she put her insulated Yeti in the freezer (different brand to Hydro Flask but similar product) and the metal bottom part cracked in a few places.
I am guessing she is talking about the protective metal plate that goes over the bottom of Yeti cups to protect the vacuum seal.
The cup would still likely work and insulate fine but this is proof that freezing an insulated bottle does actually have the potential to cause damage to it.
Why Would You Want To Freeze a Hydro Flask?
You might want to put your Hydro Flask in the freezer overnight so your drink freezes and you've got an ice cold drink in the morning that you can take with you all day.
But another common reason people want to freeze their Hydro Flasks is to pre-chill the metal so when you pour you're drink into it then it stays cold longer.
However, pre-chilling the inside of your Hydro Flask only gives you a tiny improvement in ice retention. The vacuum inside the Hydro Flask is what does the insulation and it doesn't build up a lot of heat energy that you need to remove like with an insulated cooler like Yeti.
All you're really doing is pre-chilling the thin stainless steel and while this may help a little bit it won't do much.
Can You Freeze an Empty Hydro Flask?
What about freezing an empty Hydro Flask? Can you put an empty Hydro Flask in the freezer?
If you're just trying to pre-chill you bottle and if there is nothing in there can you safely put it in the freezer? Or could this still potentially harm your Hydro Flask?
In theory the only negative I can see from freezing a Hydro Flask is the liquid inside expanding as it turns into ice and breaking your bottle because it puts pressure on the walls and vacuum seal, ultimately bending and breaking it.
However, if your bottle is completely empty this won't happen and it should be 100% fine.
Hydro Flasks are made from strong stainless steel and they are designed to hold iced water, which is often below 0ºC (32ºF) on the inside, and they are also designed to be used in all environments. Including sub-freezing temperature climates like at the snow.
If they can handle cold inside and outside temperatures in the wild then there is no reason they shouldn't be able to handle them in your freezer, assuming there is no liquid inside the cup that turns to ice and expands.
I could also see someone placing something already frozen (like ice cubes or ice cream) in their Hydro Flask and placing this in the freezer either with the lid on or off.
Because the items are already frozen they don't have any more expanding to do and so they shouldn't put any pressure on your Hydro Flask and shouldn't be able to damage it.
In fact Hydro Flask's and other insulated cups and bottles are actually a great way to keep ice cream frozen without a freezer.
Will Freezing Your Hydro Flask Void Your Warranty?
Hydro Flask offers a limited lifetime warranty on all their bottles, cups and mugs. However, this protects you against manufacturing defects not against you breaking your bottles.
If you go against their product care guidelines there is a chance that it may void your warranty.
On Hydro Flask's warranty page they state:
Hydro Flask will replace any product found to be defective within the scope of normal and appropriate use.
While they don't state exactly what “normal and appropriate use” means usually this means following the care instructions.
Given their care instructions tell you not to freeze the Hydro Flask there is a chance your warranty claim might not be approved.
Now if Hydro Flask don't find out why your bottle broke you MAY be able to get a replacement, but that's a big what if. If they find out you froze your Hydro Flask you may have to buy another one.