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Enjoy a hot or cold beverage wherever you travel, with these best-rated flasks and insulated mugs
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Our top picks held drinks’ temperatures for at least five hours – some lasted for a whopping 28 hours
If you can’t stand your tea being tepid or your water turning lukewarm, an insulated flask could be the answer. Whether used during the commute, long car journeys or nippy outdoor trips, some flasks will keep your beverages hot for 24 hours or more, while others can manage until lunchtime.
When it comes to choosing the best flask for your needs, think about the size, and whether you’re more likely to use it for hot or cold beverages. Water bottle-style vessels are best for chilled drinks, while travel mugs are better for taking quick sips of coffee. Then there are the more capacious flasks that tend to come with a cup for leisurely mugfulls of teas and soups.
Ultimately, what makes a flask worth your money is it’s ability to slow down heat transfer – either in or out – via a layer of almost airless space sandwiched between the flask’s inner and outer walls.
You may also want to consider helpful features that set one flask apart from the next, whether that’s carry-loops and handles, clever mouthpieces and incorporated cups, and even self-cleaning technology.
Keep reading to find out which flasks impressed us the most.
A selection of the best flasks that we tested for this review
First and foremost, flasks had to keep drinks hot or cold as promised, to make it onto our list. We assessed the brands’ claims by filling the flasks with boiled water (or iced water), and drank from them after a number of hours, to see if the temperature had held. We also considered how easy the flasks were to use and any design features that made them a joy to drink from, as well as mouthpieces, lids, handles and more. Generally, they had to be leak-proof – although, there are a couple of entries that aren’t, but more on that later.
A selection of the best flasks that we tested for this review
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There’s so much to like about this little flask from Thermos. On first impressions, it has a sleek, simple look to it – it’s slim, compact, and the lightest of all of the flasks we tried, making it ideal for taking it with you on the go.
There’s a little button that releases the lid, so opening the flask is a breeze, and the mouthpiece is one of the best (if not the best) we tried – wide and curved, for effortless, comfortable sipping.
When it came to the temperature test, our water was still chilled after a full 24 hours, as promised. Meanwhile, coffees and teas were still piping hot after 10 hours, so rest assured this flask will keep drinks toasty until the commute home.
This 700ml flask boasts all the perks of a larger option while stripping away the extra bulk. With a copper coating to improve heat preservation, it boasts the ability to keep drinks hot for up to eight hours. Impressively, we found ours was still nice and warm after around 20 hours, which is pretty good going. Equally impressive was the flask’s ability to keep drinks chilled – there were still ice cubes in our cold water after 24 hours.
Should you prefer sipping hot tea and coffee from a cup rather than straight from the flask, this is a brilliant, compact choice. Unscrew the flask’s lid and it becomes a cup, although, admittedly, quite a small one, so you will probably need to fill it a few times to quench your thirst.
The flask isn’t dishwasher safe but this is a minor annoyance with an otherwise very efficient and purse-friendly piece of kit.
The unlikely product to have taken TikTok by storm, Stanley’s quencher flowstate can barely stay in stock. But is it worth the (considerable) splurge? Boasting a 1.2l capacity, the reusable tumbler keeps cold drinks chilled for up to 11 hours (or two days when iced). We tested these claims with an ice-cold smoothie, which stayed deliciously chilled. The ergonomic handle adds to its ease of use, while the narrow base that fits some (but not all) car cup-holders is a nice touch.
Though it’s easy to switch between the three lid positions, the full-cover top failed to pass the leak-proof test. This completely rules out the quencher in terms of carrying it loose in a bag, which is quite a big drawback, considering the price. There’s also no denying it’s heavy, and the sheer size of the thing is slightly impractical for lugging around a city during the commute. But, when working from home, we appreciated the large capacity, as it helped boost our water intake (the colours are pretty, too).
The smallest of the flasks we put to the test is Le Creuset’s travel mug – a smart, compact and robust choice from the cookware brand. Although, the lid does take a bit of force to open and close, which might be a deal-breaker for some. It closes with a reassuring snap, though, so we felt confident it wouldn’t leak a drop. Despite the brand not specifically describing the flask as leaf-proof, we found it didn’t leak at all while we were putting it to the test.
It has a simple, utilitarian look to it, with a nice metallic finish, incorporating the signature Le Creuset three-ring design, while the lid sports the brand’s bright volcanic orange hue (the flask is also available as blue or red versions). We also liked that it’s been designed with a rubbery base, which ensures it won’t clang when you set it down.
There’s no knocking its heat retention, either, as this little flask kept drinks piping hot after six hours. Meanwhile, cold water stayed lovely and chilled all day long.
While this is a strapping flask from Stanley, it looks more streamlined and contemporary than the drinkware veteran’s classic designs. It’s a good size, but doesn’t feel overly bulky, and it promises to keep drinks hot for up to 20 hours, and cold for 24. Happily, these claims stood up during testing.
The lid doubles as an insulated cup, and, while it’s modestly sized, we think it’s big enough. There’s no chance of spills, as you might expect from a screw-in stopper, while little gaps in the stopper mean you can pour without having to unscrew it all the way. It’s a sturdy flask that gets the job done.
As Thermos has become synonymous with insulated flasks, naturally, the supersize “steel king” was going to be pretty hard to beat. It has a whopping 1.2l capacity, and we were genuinely quite stunned by how hot it kept our water over 24 hours. Most of the ice in our cold drink was still solid after 24 hours, too – you could fill your Thermos in the morning and it will still be refreshingly cool the following day.
It’s sturdy but surprisingly lightweight for its size, and the handle, which is collapsible (to save on space), helps with one-handed carrying and pouring. Everything about the steel king feels exceptionally well-made – from the thick-rimmed stainless steel cup (which doesn’t have a handle but is still nicely capacious) to the twist and pour stopper. Our one quibble would be the stainless steel cup can feel hot in your hands when the liquid inside is especially scorching. However, never having to completely remove the screw cap before pouring will make for smoother al fresco pit stops. A classic for a reason, we can’t knock it.
A conscientious choice when it comes to the materials used and environmental impact, this insulated flask from Ocean Bottle is largely made up of recycled stainless steel and ocean-bound plastic. On top of this, the brand says buying one bottle will fund efforts to prevent the equivalent of 1,000 plastic bottles from ending up in the ocean as plastic waste – so you can feel genuinely good about buying this one.
Water, coffee and even thicker smoothies and soups aren’t off limits, thanks to the bottle-esque mouthpiece – although, we did find the mouthpiece can momentarily drip slightly once the lid has been removed.
Easy to grab, owing to the flexible carry loop, you can unscrew the larger lid for cleaning and chucking in ice. Our drinks were still impressively hot after six hours and refreshingly chilled after the same amount of time – cold enough that some of the ice we dropped in there was still intact.
Sometimes, it just feels better to drink from an actual mug than a flask – particularly when you’re not actually heading into the wild, but sitting at your desk, wanting your tea or coffee to stay hot for a few hours longer.
This insulated mug isn’t leak-proof, so you won’t be carrying it around in your bag, but if you tend to forget about your cups of tea until they’ve turned tepid, it’s ideal. The matte finish is nice in the hand, and while the brand doesn’t specify for how long it should keep drinks hot or cold, our boiled water was still fairly hot after four hours, which is all you really need for a tumbler like this.
When it came to ease of use, the lid can be placed on at any angle, and the mouthpiece slides open and close easily. The mouthpiece can also be removed completely, if you’d prefer to drink straight from the mug.
This flask is robust enough for outdoorsy excursions, but not so bulky that you wouldn’t reach for it for everyday use, so it’s a good choice for taking to work, too. While Yeti doesn’t specify a maximum heat retention time, we found that our water was still hot after 24 hours, while some of the ice in our cold water managed to survive for just as long.
Everything from the matte surface to the range of fun colours on offer suggests high-quality materials. We are also big fans of the aptly named hotshot cap, which, once swivelled to one side, will let you sip from any angle. However, something to remind us whether or not the swivel mechanism had been ‘closed’ would have been really helpful.
What we consider to be the perfect amount of liquid flows through at the perfect speed (although this will be quite subjective) and the hotshot cap didn’t let us down when it came to being completely leak-free.
A perk of Ohelo’s tumbler is the strainer, which we found worked well with our loose-leaf tea, but keep in mind you can’t easily remove the tea leaves on the go. Still, you could also use it for fruit infusions or lumpy protein shakes. To drink, you just need to twist the lid until it clicks into place, letting you know it’s open. The lid proved to be leak-free, and it’s quite helpful that you can take sips from anywhere around the lid, rather than just one mouthpiece.
The lid needs to be taken apart to be cleaned, and putting it back together is a little fiddly, but we got the hang of it. As for heat retention abilities, this little tumbler performs brilliantly – hot water was still impressively hot after six hours, and chilled after 12.
Sleek and plastic-free, this flask from Klean Kanteen is an efficient and eco-conscious choice. While not quite as capacious (750ml) as the flasks from Thermos (£23, Amazon.co.uk) and Zwilling (£31.95, Zwilling.com) despite its fairly bulky design, it’s still going to be an excellent choice for bringing on longer outdoor adventures.
It performed ludicrously well when it came to preserving drink temperatures – our hot water was piping hot after 28 hours. We were dubious about claims that it could keep iced water iced for 90 hours, and were flabbergasted to find it does exactly that (yes, really, almost four days).
Leakproof and cleverly designed, the flask features a twist-and-pour cap, which can be poured from any angle – while slightly splashy if you don’t open it enough (or indeed too much), this is a really nifty way to save time and prevent some of the heat from escaping.
We loved how capacious the stainless steel lid was (216ml), and appreciated the wide mouth for comfortable sipping – perfect when you’re gasping for a big cup of tea.
There’s something satisfyingly simple about this travel mug from Contigo. Press the large button on the lid, and your beverage will flow from a hole in the lid. As the flow of liquid is more concentrated than it is from larger mouthpieces, it feels almost similar to a mini vortex, which is fun. Our water was hot after five hours, and cold after 12.
Drinking from this flask is a one-handed operation, as you don’t need to unscrew the lid before taking a sip. The lock on the lid will also prevent the button from being pressed when you don’t want it to be – say, when it’s being pushed up against your laptop in your bag. The flask is also very compact, narrow (making it easy to hold in one hand) and lightweight to carry. It’s a sleek bit of kit when it comes to design as well, with its all-over metallic finish, although there’s a range of other colours to choose from, too.
If you feel uneasy about water quality while travelling, Larq’s self-cleaning water bottle is a high-tech investment that has blazed a trail with its patented UV-C light hidden in the lid, eliminating nearly all (99.9 per cent) of bio-contaminants inside.
Looking a little sci-fi, the flask has a button on the lid, which can be pressed for either a short (one minute) UV-C cycle or you can choose adventure mode (three minutes) for extra peace of mind. Beneath the intimidating tech, though, the purevis is also just an excellent flask – our water remained hot after 12 hours, and there were still cubes of ice in our cold water after 24 hours. Importantly, please note purification will be less effective with ice in the bottle, as this may partially block the UV-C light.
A clean bottle should help to keep that musty bottle smell at bay, and, while we admit we may have been swayed by the knoweldge our water was completely clean, we did find our water tasted fresher for being purified. We liked that the bottle will clean itself automatically every two hours and, unlike the rest of our tech, only needs to be charged every month or so. It is worth noting the brand doesn’t recommend using the bottle for drinks such as coffee and tea.
Chilly’s has become somewhat synonymous with stylish drinkware – from dreamy ombre to abstract and floral bottles, there are plenty of styles to choose from. While you can use the brand’s insulated bottles for holding hot drinks (ours did a good job of keeping water piping hot for 24 hours) we would say we preferred using ours for keeping drinks cold. Some of the ice in our cold water was still intact after 24 hours and, naturally, the water was refreshingly chilled.
The series two bottles boast an antimicrobial drinking collar, which is dreamy to drink from and can be removed easily when it comes to cleaning the bottle, or dropping in ice cubes. This can sometimes open with the lid when it hasn’t been screwed on tightly enough, though, but the lid itself is completely leak-proof. Plus, the handle on the lid wins major points in terms of portability, while the protective rubber base means you don’t need to worry about making an obnoxious clang when setting down the flask.
This is a really solid little Thermos that does pretty much everything you’d ask of a flask. Thermos claims the flask retains temperatures for 24 hours, and it certainly did keep water cold and coffee warm over the full period. We were particularly impressed by how secure the flask felt, and we had no concerns about it leaking while bouncing around in our work bag on the Tube, in the car, or even while cycling, so it’s ideal for commuting.
The silicone rings make the flask feel extra sturdy, which we appreciated when out hiking, but, for most outdoor adventures, we’d probably opt for a flask that has a greater volume. That being said, it’s lightweight and has a decent 500ml capacity, which feels just right for taking tea or coffee into the office.
As photogenic as they come, this insulated flask from Partner In Wine has been purpose-built for keeping your bottle of plonk cool for up to 24 hours. A great purchase if you really resent sipping on ever-so-slightly warm wine during the summer months, this would be perfect for filling up before picnics, festivals and any al-fresco gatherings when you would rather leave the wine cooler at home. It will fit one bottle of wine perfectly, and feels markedly lightweight for a bottle of this size (750ml).
While we weren’t able to test this flask during the summer months, we still found that fridge-chilled wine stayed suitably cold for 24 hours. There’s no chance of vino spillages, either, as we can attest that the lid, which screws on easily and securely, is leak-proof. If you like ice in your wine, it’s worth noting the mouth of the bottle is quite narrow (indeed, wine-bottle narrow), so typical ice cubes won’t fit through.
While the black colour we tested is currently sold out, there are plenty of other dreamy hues to choose from, including soft pastels and all-over stainless steel.
Sleek, compact and brilliant for sipping on the go, the Thermos superlight drinks flask was the top performer – we can’t recommend it enough for everyday use. We found our water was still piping hot after 10 hours, and it doesn’t hurt that the flask also looks great.
Lifeventure’s TiV vacuum flask also offers excellent value for money, while the Klean Kanteen flask is ludicrously good at keeping drinks hot or cold for many, many hours.
The Ocean Bottle deserves a mention for being so versatile when it comes to carrying cold water and hot drinks as well as thicker liquids such as smoothies and soups, and we love that the brand is built on the premise of protecting the ocean by reducing plastic waste.
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Plastic Vacuum Cup Or if you would prefer: