You may be finding that your Hydro Flask is not keeping water cold for a long period of time like it should. Here are the main causes of this issue and what you can do about it.
The main cause of a Hydro Flask not keeping water cold is that the vacuum sealed insulation is broken and filled with air. This issue is covered under Hydro Flask's lifetime warranty and you can contact them for a replacement bottle.
However, there are several other reasons why your Hydro Flask is not keeping water cold and it's worth checking these to see if they fix the issue before getting in contact with the company.
First, Understand How Hydro Flasks Keep Water Cold
I wrote a full article on exactly how Hydro Flask bottles work to keep things cold and hot, but I will quickly summarise here as it can help us to identify potential problems.
Hydro Flasks are able to insulate so well and keep items hot and cold for so longer because of one main thing: a vacuum
Hydro Flask bottles have an inner and outer wall with a gap in the middle. In that space they remove all the air and create a vacuum. They then seal it up so nothing can get into that space.
It is the vacuum that creates the insulation. Most heat can't pass through a vacuum so your water stays cold for so long because no heat can get inside to warm it up.
How Long Should Water Stay Cold In a Hydro Flask?
Hydro Flask claim to be able to hold ice for 24+ hours and through personally using my 18 oz Standard Mouth Hydro Flask I can say that I get similar results when I completely fill it with ice and cold water.
Here are some rough estimates on how long a Hydro Flask should keep water cold for. This will vary depending on size and how hot it is outside:
- Full of ice – 24+ hours
- Half ice/Half cold water – 18 hours
- Little bit of ice and cold water – 12+ hours
- Cold water – 4-6 hours
- Room temperature water – 0 hours
Reasons Your Hydro Flask Is Not Keeping Water Cold
Below are the 6 main reasons I have seen people have issues with their Hydro Flask not keeping water cold (or hot) for a long period of time.
You can also check out my tips on keeping ice longer in your Hydro Flask if you want your drinks to stay as cold as possible for as long as possible.
1. The Vacuum Insulation is Compromised
If you're experiencing significant issues with your Hydro Flask being able to keep water cold for a long period of time then the most likely cause is the insulation being compromised.
As we talked about Hydro Flasks have an inner and outer wall with the space in between being a vacuum and having nearly no particles for heat to pass through.
As I talked about in my article on whether or not Hydro Flasks stop working this actually shouldn't happen to your bottle through regular usage and Hydro Flasks are actually backed by a lifetime warranty for issues with the vacuum seal.
If the vacuum seal is broken because of something you did, like dropping or damaging the bottle significantly or by putting it through the dishwasher, then you won't be covered.
If you think this is your issue then click here to claim your warranty with Hydro Flask.
2. You're Not Using Enough Ice
When you fill your Hydro Flask up with water and some ice the water will immediately melt much of the ice as the ice lowers the temperature of the water.
If you don't use enough ice then the water can melt all of your ice really quickly in your Hydro Flask and this means your water likely isn't as cold as you want it to be to start out with.
This semi-cold water will then warm up much faster than water with more ice in it.
So maybe water isn't staying cold for long in your Hydro Flask because you aren't using enough ice. You want to use a high ice-to-water ratio. I personally fill up my Hydro Flask almost completely with ice and then add water.
This also allows me to add more water when I have finished drinking my bottle and the water I add quickly cools down because there is still lots of ice left over.
3. You're Using Warm Tap Water
To keep water cold in your Hydro Flask as long as possible you want to be filling it up with pre-chilled water.
If you fill up your Hydro Flask with room temperature water then this will quickly melt whatever ice you have in your Hydro Flask bottle and your bottle want keep the water cold as long.
So when possible always use pre-chilled water from the fridge. But remember you shouldn't put your Hydro Flask in the fridge or freezer.
4. You're Leaving The Lid Open
When I'm sitting at my desk working on the latest article for The Cooler Box or one of my other websites I'll often have my Hydro Flask there next to me with the lid off ready to drink.
This is practical as I am constantly sipping water throughout the day.
However, leaving the lid off your Hydro Flask makes the water warm up faster. This is because the mouth opening is the main place heat can get into your Hydro Flask.
The plastic lids provide some insulation but if you leave them off then heat and warm air can easily get into your Hydro Flask warming up your water.
It should still keep ice longer than a regular glass or bottle, but for best results leave your lid on where possible.
5. It's Being Exposed To Too Much Heat
While Hydro Flasks are great at insulating they aren't perfect and bits of heat do get into the bottle.
If you're exposing the bottle to a lot of external heat then the water inside will warm up faster. Having your bottle in direct sunlight, especially if it's a dark color, can cause your water not to stay cold as long.
Light colored Hydro Flask are best for keeping water cold the longest as they reflect the most light and also the most heat. Click here to do the quiz on which Hydro Flask color is perfect for you.
Having it up against your body, warm computer or other machinery or the warm ground can also have a negative affect on how long it can keep water cold.
So keep it away from direct contact with hot things where possible.
6. You're Drinking The Water
The more empty space in a Hydro Flask the quicker water will warm up.
An 18 oz Hydro Flask filled with ice and cold water will keep that water colder much longer than a 64 oz Hydro Flask that only has 18 oz of ice and water in it.
The empty space fills with air and heat and causes the water in your Hydro Flask to warm up more quickly.
So if you have a large Hydro Flask and it is mostly empty then this may be why water isn't staying cold in your Hydro Flask.
Time To Update Your Hydro Flask?
Maybe your Hydro Flask is old and it's time for a new one or maybe you've always wanted a different color or a different size. If your Hydro Flask isn't keeping water cold then maybe it's time for an upgrade to a newer model.