Forget skilled baristas serving flawlessly frothed cappuccinos at the perfect temperature. No tea, coffee or hot chocolate tastes better than one served piping hot on the summit of a wind-whipped hill or mountain. Ever. Which is why investing in the best hiking flasks makes perfect sense.
Ideally, your flask will keep drinks as scalding as molten lava, generate clouds of steam when you pour, and refresh and restore flagging spirits and limbs with the electrifying power of a Baptist preacher in full flow. Amen.
Even the most cursory glance at outdoor gear and camping websites reveals a wide range of insulated flasks vying to deliver your mid-walk pick-me-up. Short, tall, fat, thin, light, heavy, wide-mouthed or push-button lids, cups, handles… the choice seems endless to deliver the basic necessity of a hot drink (or hot food).
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- Wondering 'should I buy a hydration pack?' Check out our advice
The question is simply to find the best hiking flask for you. Do you need a flask to serve a fresh-tasting brew on a summer’s stroll through a country park? Or are you relying on a flask to deliver some inner-warmth when you’re stood on a gale-lashed summit in mid-winter, or even to bring you back to life after an icy cold wild swimming experience?
Here’s our selection of the best hiking flasks for adventurers, wherever, whenever and however they’re embracing the outdoors. The one theme that unites them is their leak-proof construction – these are flasks robust enough to be carried in backpacks.
The best hiking flasks you can buy
There’s a family of four sizes in the Lifeventure TiV range, so finding the volume of vacuum flask that suits your needs should be easy, from a small, solo flask to a mighty family-sized affair. Each TiV flask is copper-coated to boost heat retention, and should be good for keeping hot drinks hot for up to eight hours, while keeping cold drinks chilled for as long as 24 hours (tip: add ice cubes to extend the cooling effect).
The deep screw stopper provides a reassuringly leak-proof closure, but you’ll need to unscrew it completely to pour a drink. Out on the trail, the stainless steel lid doubles as a handy cup and is a useful size on all four flasks in the range, while the slim body makes it easy to pour single-handedly.
The bright colours of the Primus Vacuum Bottle range are, er, not just a pretty face on a functional item of outdoor kit. The powder coating gives enough purchase that it’s possible to unscrew the lid without taking off your gloves, which is a massive bonus when the mercury tumbles. Then it’s simply a question of pushing down the button in the centre of the stopper and pouring your drink. It’s not the neatest spout, and is far from ideal if you fancy swigging cold drinks directly from the flask, but on the plus side it traps heat inside to keep drinks warmer for longer. This ‘sealed’ stopper also makes it a little harder to assess how much drink is left in the Primus Vacuum Bottle – walkers will have to count the cupfuls they pour to keep track.
The lid serves as a handy cup, although as with most flasks in this review, the volume is pretty small, especially if you’re accustomed to the giant beakers of high street coffee outlets.
After use, the narrow opening makes cleaning a little difficult, particularly if you take milk in your coffee or fill the flask with soup, although long brushes are available. The click-close button also disassembles for cleaning, but it’s far from obvious how to do this.
If there’s one thing more likely to turn your walking buddies green with envy than having a flask of hot drink available throughout the day, it’s tucking into a hot meal while they chomp on soggy sandwiches. Pasta with pesto and cheese, chunky soups and hearty stews… whatever your midday masterpiece, this robust Thermos Stainless King Food Flask will keep it hot until it’s time for lunch.
The flask itself is short and fat, its 9.4cm diameter too wide to slide into a side pocket of a rucksack, but at only 14.2cm tall it squeezes inside a pack with no trouble. The lid conceals a handy, full-size folding spoon and you could use the insulated lid as a bowl if you’re sharing your meal, although most walkers should be able to manage the full contents on their own.
Thermos claims that once sealed, the Stainless King Food Flask will keep hot food hot for nine hours and cold food chilled for 14 hours. For optimum performance it pays to pre-heat the flask with boiling water prior to filling it with food, and once the wide lid is removed it doesn’t take long for an icy wind to cool food down.
The wide mouth does, however, make this pot easy to clean – only larger hands won’t fit inside it, and the five-year guarantee is a welcome case of a manufacturer putting its money where its mouth is.
The walker nominated to carry this giant flask in his or her rucksack has truly drawn the short straw… until the first drinks break… and the second… and the third! The great advantage of this double-wall vacuum insulation and the generous volume is that drinks stay unbelievably hot. Stanley claims a ‘stay hot’ time of 40 hours, and if you pack it with ice it will spend up to six days frozen!
On the other hand, it is a beast to carry, especially in a smaller day pack, and while the collapsible handle is useful for pouring when the flask is full, especially if you don’t have baseball mitts for hands, it can snag on clothes when you pull the flask out of a rucksack.
The fact that you’re as likely to see the Stanley Classic Vacuum Bottle on a building site as you are on a hilltop tells you everything you need to know about the flask’s bombproof build quality, which is reassuringly backed up by a lifetime warranty.
You’ll need a long brush to reach the bottom of the flask for cleaning, although it is dishwasher-proof – if your dishwasher is big enough to accommodate it!
The slim, stylish GSI Outdoors Microlite 350 Flip applies the spout technology of a water bottle to the science of keeping drinks kettle hot or ice cube cold. The flip-top lid and pouring spout lets you swig straight from the flask, which is ideal unless your drink is too hot to swallow (and watch out for your fillings if you’ve packed the bottle with ice). You can, of course, simply take a mug along with you (there’s no lid cup on the top, unlike the other flasks in this test), and if you want a flask to double up for your commutes it’s easy to have a mug ready on your desk at work.
The ultra-thin, 2mm walls of the flask lend it the slenderness of a supermodel while swallowing a surprisingly large volume of fluid given its dimensions – GSI reckons it can carry 25 percent more liquid than traditional vacuum bottles of the same size.
The push-button, flip-top cap allows one-handed access, which is convenient if you’ve got a map, GPS, camera or walking pole in your other hand.
As for the insulation, the Microlite 350 Flip will keep hot drinks hot for eight hours and keep cold drinks chilled for as long as 16 hours.
While insulated travel mugs offer a far greener alternative to disposable coffee shop beakers, suspicions about the security of their seals have left walkers reticent about trusting them beyond campsite use. As scores of positive reviews attest, however, Camelbak has solved the problem thanks to its Hot Cap, which converts insulated mugs and bottles into flasks. Cleverly, the Hot Cap is also compatible with Camelbak’s Chute Mag and Eddy+ water bottles, turning them into cold drink flasks.
The lid’s rotating twist valve opens and closes the flow of liquid, with the added convenience of 360-degree drinking from any side of the mug (handy for keeping your eyes on the road if you’re taking a swig while driving).
Out on the trail, the no-slip textured flask fits nicely in the hand, keeps hot drinks hot for six hours (a much better performance than most travel mugs), and then is straightforward to disassemble for a thorough clean.
Designed by camping and hiking specialist Vango, the stainless steel Magma Flask delivers everything a walker could want from a flask. Like Henry Ford’s proverbial Model T, you can choose any colour so long as it’s black, but that simplicity aside, the copper-coated double wall vacuum flask delivers impressive insulation to retain heat and keep cold drinks cool.
There’s no fancy lid – just unscrew the top and pour your cuppa into the lined cup.
The Vango Magma Flask is available in three sizes – 500ml, 750ml and 1-litre – so there’s a good range of choice from solo flask to family drinks, and all for bargain prices.
Choosing the best hiking flask for your outdoor adventures
Volume
This is an entirely personal decision – are you carrying a hot drink only for yourself, for you and a partner, or for the whole family? For coffee lovers weaned on the giant beakers of Starbucks and Costa, the 350ml, one-person models may not be turn out to be the best hiking flask for a long day in the hills.
Dimensions
Where will you carry your flask? Tucked deep in your rucksack or in a side pocket for swift, easy access. The diameter of some of the best hiking flasks in this test is too wide to slide into many daypack side pockets. It’s also worth bearing in mind that a flask which fits snugly in your hand is easier to pour and avoids having to take off your gloves when the temperature drops.
Top/stopper
The traditional, deep, screw-in stoppers should provide the most secure seal (although most modern flasks are reliable), but they need two hands to unscrew and pour, and they let heat escape each time they are undone. Click tops that let you pour a drink without unscrewing the top retain heat better, but they don’t let soup flow very easily and they can be awkward to dismantle and clean. Drinking spouts that allow you to drink straight from the flask seem convenient, but if the flask’s insulation is any good the drink will be too hot to swallow for a long time.
Opening
If you want to use your flask for hot food you’ll need a wider mouth and shallower depth to reach the bottom with a fork or spoon. The wider mouth makes cleaning easier because most people will be able to squeeze a hand and scourer inside.
Insulation
The primary reason for taking the best hiking flasks on a walk is to keep hot drinks hot or chilled drinks cold, so their insulation performance really matters. Pre-heating or pre-cooling flasks can make a significant difference to the heat/cold retention. Remember, too, that the more liquid in a flask the better it will retain its temperature, so larger volume flasks will outperform smaller rivals.
