9 Best Ways To Keep Water Cold Longer In a Nalgene

Nalgenes are great water bottles, with one glaring flaw — they’re pretty terrible at keeping drinks cold.

If you fill your bottle with ice water on a hot summer day, the ice will be fully melted in a couple of hours and your water will be warm not too long after. See how long drinks stay cold in a Nalgene.

But it doesn’t have to be that way.  

To keep water cold in a Nalgene, start with the coldest water possible and add plenty of the largest ice cubes that will fit. Freezing a half-full bottle before adding water works even better. Keep your bottle out of direct sunlight (indoors or, better yet, in a fridge whenever possible) and use a neoprene sleeve or cloth to provide insulation. 

Below are nine of the best ways I’ve found to keep water cold in a Nalgene for as long as possible.

Combining methods will take you even further. 

For example, a pre-frozen bottle, filled with the coldest water possible, in a neoprene sleeve, kept out of direct sunlight may stay cold for the entire day. 

1. Use An Insulating Cover

A neoprene sleeve will help keep your water cold for a couple hours longer than the bottle on its own — by trapping cold air in and keeping hot air out.

And aside from providing insulation, neoprene sleeves offer a few other nice benefits as well:

  • They reduce and absorb sweat
  • Most have built-in handles to make carrying your Nalgene easier.
  • They provide additional protection against drops and damage.

Nalgene sells their own Neoprene sleeves for their bottles which are pretty good or there are also a variety of other versions out there too.

This is one of the most effective ways at keeping drinks cold longer in your Nalgene.

Nalgene Neoprene Bottle Sleeve (for 32 oz)

This handy neoprene sleeve fits perfectly onto any 32 oz Nalgene bottle and helps to keep your drinks colder longer and will reduce sweating. Features a draw string for a tight fit and a side clip for easy carrying.

Buy Now at Amazon

2. Wrap It In A Tea Towel, Blanket, Or Sweater

I don't personally own an neoprene sleeve for my Nalgene but I have regularly used towels or sweaters to keep my Nalgene cold for longer.

When going for a bushwalk I'll fill up my Nalgene with ice and cold water and then I'll wrap it in a tea towel with other items like chocolate and yogurt that I want to keep cold while on my hike.

The tea towel insulates everything from the warm outside air and the Nalgene acts like an ice pack to keep my food cold.

When I go to the beach on a hot day and take my Nalgene with me I'll wrap it up in my beach towel before putting it in my bag.

Like an insulating sleeve, wrapping your bottle in a tea towel, blanket, or sweater will help keep the cold air in and the hot air out. 

Any piece of fabric will help, but wool, flannel, fleece, and terry cloth provide the best insulation. 

Just be careful not to use any piece of clothing you don’t want to get wet because, as your bottle warms, it will start to sweat and may make your clothing item wet in the process.

3. Wrap In A Wet Cloth In A Breeze

While the above methods provide insulation and slow down warming, this method can actually help make your water colder (at least a little bit). 

Simply wrap your Nalgene in a wet towel or cloth and let it sit in the breeze. If you’re inside, a fan works well too.

As the water in the towel evaporates, heat is carried away, cooling the contents of your bottle. 

I'll be honest with you, given Nalgene bottles are plastic this is not the most effective method for keeping your drink cold. It can also get a bit messy. But it CAN work in some circumstances so worth a try on a breezy day.

4. Keep Your Bottle Out Of Direct Sunlight

Nothing warms water in a Nalgene faster than sitting in the sun. 

Stick it under a picnic table, behind a tree, or even under your car if you have to — anywhere but in direct sunlight. 

And no matter which other methods you choose, keeping your bottle in the shade (or better yet, indoors) is recommended. 

5. Use Ice

It may come as no surprise that adding ice to your water will help it stay cold longer. 

Just a few things to keep in mind:

  • The more ice you use, the longer it will last. 
  • Larger cubes last longer than smaller cubes.
  • While it won’t help your water stay cold any longer, I just wanted to give a shout out to nugget ice because it’s amazing. 

This is one reason I love the wide mouth Nalgene bottles over the narrow mouth bottles. They are so much easier to fill with ice and with large chunks of ice.

For a full day hike I'll completely fill my Nalgene with ice to the top and then add cold water from the fridge. The more ice you can use the longer it'll stay cold.

6. Pre-Freeze Your Nalgene 

Even better than using ice cubes, pre-freezing a half full bottle of water on its side the night before will leave you with one large chunk of ice that will melt much slower and keep your Nalgene cold for hours longer.

On a hot summer day (when you want ice cold water the most), ice cubes will usually melt in about two or three hours.

If you pre-freeze your bottle, the chunk of ice can last for six to eight hours or more.

A pretty significant difference. 

Just be careful anytime you freeze water in your Nalgene. If you fill more than halfway, there won’t be enough room for the water to expand as it turns to ice and this could potentially break your Nalgene.

I like to fill mine about half full of water and then throw it in the freezer lying down. You can also do it standing up and then add more ice to the top before filling it up with cold water from the fridge.

Overfilling a Nalgene before freezing is one of the easiest ways to break a Nalgene Bottle.

7. Start With Cold Water (Not Room Temperature)

The lower the initial temperature of your water, the more time it takes for it to warm. 

It might seem pretty obvious, but it didn’t initially occur to me how big of a difference it can actually make.

Even if you’re using ice, pouring room temperature water over ice cubes partially melts them and they won’t last nearly as long. 

If I know I’m going out later, I fill up my Nalgene with ice and then add cold water from the fridge. The cold water is near freezing already so it won't melt the ice as much and you're water will stay colder for longer.

7. Use Whiskey Stones Or Ice Sticks

If you drink anything other than water from your Nalgene, you know that a watered down drink from melted ice is always a bummer. 

If I’m drinking iced tea or iced coffee from my Nalgene, I opt for stainless steel ice cubes or reusable ice sticks instead of ice. 

They don’t keep water cold for quite as long, but they do a good enough job and my drink ends up tasting better for longer. 

Stainless Steel Ice Cubes - Whiskey Stones (16 Pack)

These reusable stainless steel ice cubes chill your drink without diluting it. They are made from food grade stainless steel that is 1mm thick with an interior of 35% glycerin + water which has a freezing point of -12ºC (10.4ºF) - keeping your drinks even colder than regular ice cubes.

Buy Now at Amazon
03/07/2024 01:22 pm GMT

9. Keep It In The Fridge When You Can

For years I ended up drinking warm water during afternoons in my office. 

I’d start off with a nice, cold bottle on my desk in the morning and by mid-afternoon it was pretty much at room temperature.

The sad part is, the refrigerator was only about 15 feet away the whole time. 

Now, when I’m working, my Nalgene waits for me in the refrigerator. Whenever I want a sip, it’s just an added bonus that I’m reminded to get up and stretch and give my eyes a rest from staring at my monitor.