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Water Bottle Insulation for Winter Hiking

Water Bottle Insulation for Winter Hiking

An insulated water bottle sleeve is one of the ways you can keep your water from freezing on a winter hike. Most are designed to fit 32 oz (1 liter) bottles, including wide-mouth Nalgene bottles, which are better for winter use because they’re less likely to freeze closed than ones with narrow necks. Most winter hikers fill their water bottles with boiling hot water when they pack in the morning and keep it insulated and hot until it’s needed.

Unfortunately, insulated water bottle sleeves have become increasingly scarce in the past few years and hard to find. I suspect the demand for them has fallen because insulated metal bottles (Hydroflask, et. al.) have become so popular. But the problem with insulated thermos-style bottles, which you’ll quickly find out if you try to use them for winter hiking, is that they keep your water undrinkably hot. It’s important to drink a LOT of water when winter hiking, so a solution that keeps your water too hot to drink is a fail. A thermos is fine for carrying some hot soup (Campbell’s Tomato Soup makes a great mid-hike pick me up), but it’s a cumbersome solution for carrying 3 liters of hot water.

Switch Bottles When They’re Empty

I try to drink a liter of water every 2-3 hours when winter hiking and usually carry 2 to 3 one liter (32 oz) bottles of hot water on all-day winter hikes. The trick to keeping all this water from freezing is to only carry one bottle in an insulated sleeve on the outside of your backpack at a time. The rest will stay hot if you store them inside your backpack and next to an insulated jacket and the extra clothes carried in your pack. When you finish the bottle stored on the outside of your pack, just replace it with one of the ones still stored inside your pack.

Bottle Sleeves, Holsters, Boots, and Parkas

All of the insulated water bottle sleeves listed below will keep your water warm and prevent it from freezing for several hours when they’re attached to the outside of your backpack.  They’re all pretty equivalent in that regard.

Nalgene Water Bottle Sleeve

Nalgene Insulated Sleeve
The Nalgene Water Bottle Sleeve is insulated with reflective insulation to keep your bottles warm. The top closes with a zipper. It’s compatible with 32 oz Nalgene Wide Mouth Bottles (turn them upside down to get past the zipper). There is a strap sewn on the outside of the sleeve, good for gripping it by hand, and a second webbing strap that can be used to attach it to a pack with a carabiner.

View at Amazon

Forty Below Bottle Boots

Forty Below Water bottle Boot
40 Below’s Water Bottle Boots are made with Neoprene and are available in multiple sizes. They don’t have zippers which makes it much easier to open them if you’re wearing mittens or bulky winter gloves. They’re compatible with 32 oz Nalgene Bottles and the German Hunersdorf Bottles favored by mountaineers because you can open them without removing your gloves. They come with a sewn-on webbing strap that can be used to secure them to your hip belt or backpack with a carabiner.

View at

Hyperlite Mountain Gear “The Insulator”

HMG The Insulator
The Hyperlite Mountain Gear Insulator is a 4.3-ounce Dyneema water bottle sleeve insulated with Thinsulate which has a zippered top closure and a velcro strap that wraps around your hip belt, making it convenient to access your water in winter when you’re on the go.
View at Hyperlite

Outdoor Research SG Water Bottle Parka

Outdoor Research Water Bottle SG Parka
The Outdoor Research SG Bottle Parka is sized to fin 32 oz Nalgene bottles and is quite similar to the Mountainsmith Bottle Holster. It closes with a top zipper and has a velcro strap that makes it easier to attach to a backpack hip belt. However, it is outrageously expensive ($92) and probably worth a pass. OR used to make much more affordable Water Bottle Parkas, but these are extremely difficult to find new.

View at Outdoor Research

More Tips and Tricks

Fill with Boiling Water

Fill your water bottles with boiling water in the morning before you leave for your hike. An electric kettle makes this an easy process and is much faster than trying to boil water on a stove. You may also want to add a sweetener to your water to make it more drinkable. I like using herb tea because it makes cleanup so easy, but some people also use electrolyte drinks. Just remember that it has to be palatable if it’s hot.

Keep Your Bottle Upside Down

When you put a bottle in an insulated sleeve, store it upside down. This will prevent the cap and threads from freezing shut. The bottles stored inside your backpack can remain upright if they’re surrounded by warm clothes, although I also wrap mine in plastic bags to prevent a catastrophic leak.

Wide Mouth White Nalgene Bottles

If you use 32 oz Nalgene Bottles, I’d recommend using the white-colored (HDPE) polyethylene Nalgene Bottles instead of the clear ones. The white Nalgenes are several ounces lighter (3.5 oz vs. 6.25 oz) than the clear plastic bottles. Whatever you end up using, make sure that they’re wide-mouth bottles, since Nalgene and plastic bottles with a narrow neck are much more likely to freeze shut and are difficult to store inside an insulated sleeve upside down.

Hot Lunch

If you position your lunch in proximity to the hot water bottles stored in your pack, they’ll heat up your food. I like packing cheese and salami sandwiches in winter and the cheese has usually melted by the time lunch rolls around.

Snow Melting Starter

When winter backpacking, you’ll want to hold a cup of water in reserve as a starter for snow melting. Pour the water into your snow melting pot, heat it up to boiling, and slowly add snow to the pot to make more water. If you try to melt snow in a cookpot without a starter, the snow will burn (yes burn) in the pot, create a horrendous smell, and potentially burn a hole in your cookpot.

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About the author

Philip Werner has hiked and backpacked over 9500 miles in the United States and the UK and written over 3000 articles as the founder of, noted for its backpacking gear reviews and hiking FAQs. A devotee of New Hampshire and Maine hiking and backpacking, Philip has hiked all 650+ trails in the White Mountains twice and has completed 11 rounds of the 48 peaks on the White Mountains 4000 footer list with over 575 summits in all four seasons. He is also the author of Backpacking the White Mountain 4000 Footers, a free online guidebook of the best backpacking trips in the White Mountains in New Hampshire and Maine. He lives in New Hampshire. Click here to subscribe to the SectionHiker newsletter.


  1. When I go overnight backpacking, I usually leave a quarter of water from the previous night before adding boiling hot water in the morning. This way even if you’re using a double-wall bottle, you don’t have to deal with piping hot water. In the case you’re unable to retain water before filling up, fill up your water 3/4 of the way and cool it down with snow; in the winter snow is usually abound. Having a thermos is way more convenient than buying extra insulation: you don’t have to deal with the cap freezing up, since the water never goes under freezing temperature.

    • But you don’t have that luxury to stand around on a day hike and melt snow or cool your hot water. This article is focused on how to carry your water during the day to keep it from freezing and to keep it drinkable. Carrying three 32 oz thermoses doesn’t cut it for me. I explain a much simpler approach and one you can do at dawn in your kitchen when you’re still befuddled from sleep.

      For overnight trips, I’ve never had my water freeze overnight in a wide bottle when buried upside down and in snow which is an excellent insulator. You can also sleep with a hot water bottle, which is rather nice. But it’s all good. Thermoses work too,

      • I’ve been thinking of this lately.
        Good article and comment. Happy New Year!!

      • Would adjusting the water temperature before going out not possible? The water in your thermos, given you start at 40-70 degree, will not go down to 20 within 8hrs. That’s what a thermos is for to begin with: keeping water temperature steady. I’ve tried your way, but with a thermos there are less fiddle factors. If concerned with weight, try GSI Microlite.

        • I’m sure you could if you are equipped and awake enough to do it. But now do it for multiple thermos bottles for an 8+ hour hike. It just doesn’t scale. For example, an empty GSI Microlite weighs 13 oz. Are you suggesting carrying 39 ounces of empty insulated bottles in addition to 6 pounds (one liter = 2 pounds) of water for a hike requiring 3L of water? Maybe I just take longer winter hikes than you.

        • Thanks for the nice article.

          I’m wondering if I should use a “metal insulated bottle” or the “PE bottle + cozy” combination mentioned in this article.
          I have come up with the following ideas, Could you share your thoughts?

          ?Your ideas
          one PE bottle & cozy= 4.8oz + 4.4oz = 9.2oz
          spare 2 PE bottle 4.8oz*2 = 9.6oz

          ?My idea
          one metal insulated bottle=13oz
          spare 2 PE bottle = 9.6oz

          13 oz – 9.2 oz = 3.8 oz difference, but considering the ease of use of the metal insulated bottle, I think it will pay for itself.

          Especially this mont-bell metal insulated bottle has quick access.
          I’m afraid that the bottle+cozy seems to be hard to open and close, and I’m afraid that I’ll end up drinking water less often.

          When the water in the metal insulated bottle runs out, I plan to refill it from the PE bottle, which I do twice a day, so it shouldn’t be too much work.

          thank you in advance

        • Winter hiking requires the development of different habits than the rest of the year and this includes hydration. I consider metal bottles in winter as a death wish even if they’re thermoses. They keep the water too hot to drink and when they get cold, they’re unusable and freeze closed. Yes, you actually want it to cool. But hey, try it.

      • Add on comment: when you add snow to your hot water to cool it down, are you purifying it somehow?

    • I struggled to find a dedicated sleeve for my drinks flask so I use a neoprene 200mm camera lens case to keep my drinks mug flask hotter for longer on winter hikes. I guess you could do the same to stop your water from freezing too. They are super light and cost around £5. You can find smaller cases that cost less.

  2. I purchased an insulated bottle bag from Equinox a couple of years ago and it has worked great so far:

  3. Your solution definitely makes sense when carrying that much water. Great article Phil: like all your articles very informative and useful.

    • Sorry If I was pushy there. I’m a moron when I get up before dawn for these winter hikes. I can boil water in an electric kettle, but higher cognitive functions like temperature adjustment, just ain’t going to happen,.

      • Not at all. I actually use an insulation sleeve with my Microlite since handling anything metal in the winter months is unpleasant and saps your body heat. I guess that’s another point on how a plastic bottle is superior.

      • As a teen, when starting a new job at 4am, I put the coffee grounds in the water in the pot on the stove like my father always did (he’d pour the coffee through a filter into his cup), then went into the bathroom to get myself ready. When I got back, the water had boiled off and the grounds were burning in the bottom of the pot. I read some writer describe it as the coffee conundrum–you have to HAVE a cup of coffee before you’re qualified to MAKE a cup of coffee.

        I have negative cognitive functionality early in the morning.

    • I bring an old ridgerest rolled up inside my pack. I put water bottles inside it for insulation. That way my water bottle insulation is multi-use

      • me too. I stuff my extra socks in one end and extra hat & mittens in the other. Keeps the water hot enough to make instant soup at lunch time.

  4. Seems like an easy & fun DIY project to make a bottle cozy

  5. I hiked yesterday in Shenandoah and my bottles all froze. Thanks for the tips! I like the idea of going upside down as that would have helped me a bit. Just ordered the Mountainsmith Bottle Holster from REI.

  6. Back when I wasn’t particularly well off financially I made cozies out of sections of old ensolite pads. Just like making a cozie for your pot, you can make them for your water bottles. I still have a couple that can be pressed into use if I”m with folks who don’t have a commercially made insulated bottle holder. Pretty simple to make if you have the pad, some duct tape and a few minutes.

  7. What do you think I use my extra pair of sox for? A pair of heavy wool sox (which you should have an extra pair of anyway) fit over the tall smart water bottles just fine.. this is usually my second liter.. The first is uninsulated but starts out hot. The second gets the sox and the third is in a hydro flask..

  8. The use of the word is supposed to be jarring. Seems to have achieved that effect.

  9. As an Amazon purchaser pointed out since the Nalgene insulated sleeve is tapered at the top, if you invert a 1 liter bottle you can’t zip close it. This makes it undesirable for winter use.

    • That’s not correct. I just verified personally that 32 oz clear and milky white Nalgene Bottles do fit in the sleeve when turned upside down and the top zippers closed just fine. Do yourself a favor and test what people write on Amazon reviews before you jump to unverified conclusions. In my experience, you have to take public reviews on shopping sites with a grain of salt. Many people have no idea what they’re talking about.

  10. Would you recommend the 40 below or the OR SG bottle parka assuming both are priced the same? (Looks like the OR is available new on ebay for about $40)

  11. so which one of these keeps the Nalgene warm for longer?

    • The mountainsmith – but honestly, the best approach is to prehydrate and keep the bottle inside your pack surrounded by your puffy for a few hours before you need to take a drink. That will keep the water boiling hot.

  12. has anyone tried reflective insulation tape around a smart water bottle?

  13. I really like this insulator from Equinox and it’s only $24. Very thick insulation, works great for me.

  14. My solution to ‘cooling’ off the hot water in the thermos…is to keep refilling a small metal non-insulated bottle, stored on the outside of my pack. When I drink it at stops…I refill with the warm water for the next stop.

  15. I have used Reflectix too make a cozy for s Nalgene bottle. Works well.

    Also, of course water does not burn. A friend suggested it is the impurities that cause the smell.

    I use an alcohol stove to get some water to start the snow melting process in my MSR windburner. Water does not “burn” in an alcohol stove. Not very efficient are -30F and melts snow to slowly by itself.

  16. I usually take two nalgene bottles and one vacuum flask. The vacuum flask keeps water hotter longer so I consider that my “emergency water” in case my hike gets extended and I use it last.

    On a group hike, I often bring a roll-up closed cell pad as a sit-upon for lunch or rest stops or for emergency ground insulation. In that case, i roll my bottles into the Ridge Rest and close the ends with spare socks and spare mitts.

    In a pinch, that old ragg wool sock that is missing a mate makes a good insulator. You can double up by keep that inside your spare hat if you are bringing a spare hat.

  17. All these insulators will run $20+ then compound the fact that you’ll carry multiple bottles it can really add up. I just want to recommend an old wool sock, toss the bottle inside. It’s not as good as the ones you purchase but it has worked for me at 18K ft in 0 degrees.

    • Chris, these days I just keep them in my pack and camel up every hour or two. But when I do carry an insulator in an outside pocket, I just carry one and swap out the bottles so the rest stay warm inside my pack. Saves cost, saves weight.

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