Hydro Flask are a fashionable US company who have made reusable flasks and water bottles immensely cool over on the West Coast of America. The Hydro Flask Wide Mouth is a quality vacuum flask employing some great tech, a lovely powder-coated exterior surface for great grip as well as excellent heat retention properties. The downside is that they are a touch on the expensive side – you don’t get this sort of style for free girl! Nothing beats a hot brew when you’re tramping around the hills on a winter hike. It’s like we’re hard-wired to appreciate that soothing warmth spreading around our bodies like a “Ready Brek” glow. My hot water was 92.3°C at 8:05pm, and by 8:05am it was 57°C – a temperature drop of 35.3°C after 12 hours. It’s still “warm” – just not as warm; and certainly not pipingly hot. My cold water with ice cubes is 5°C at 11:02 and 12 hours later its 3.5°C. If you are searching for a great value thermos flask at the lower end of the budget range then we don’t think you can do much better than the SMARDY Vacuum Insulated Water Bottle. This is a compact size flask with a smallish capacity of 430ml – this is only enough for two cups of tea.

You may think choosing a vacuum flask is a simple matter of grabbing the shiniest example in the camping shop (if it’s open!) and hoping for the best. Well, unfortunately we’ve tried that approach several times and have frequently been disappointed. One of its aims is to reduce the amount of plastic going into the ocean by encouraging the use of a steel bottle, so it is proudly 100pc BPA free. The original and, judging from the results of our temperature test, still the best. This stainless steel flask is very durable, with a silicone base to protect against dents. The two-part stopper closes securely yet pours easily and has an integrated cup. In terms of outright heat-holding performance for up to 8 hours, nothing can touch the Ultimate Series. It was the best-performing flask we tested overall. It is relatively lightweight too. And if you’re concerned that the 500ml capacity will be too small, it’s worth noting that Thermos also makes a larger 900ml version. Full SpecificationsThe heat retention capacity of the flask is exceptional. You will certainly be impressed with both the hot and cold performance. We were able to keep some tomato soup warm for 24 hours and on another occasion, some chilled orange squash remained cold after 36 hours. This is definitely enough for an overnight wild camping trip if you can handle the weight. We examined each flask and its pouring mechanism and attachments for faults. We penalised flasks that had faults affecting their usability. Thermos flasks use an ingenious mechanism which consists of dual layers separated by a vacuum cavity between them. The vacuum is a region of space with no air or anything at all in it – this creates a natural barrier to heat leaving or entering the innermost chamber holding your drink. That’s why liquids in the flask remain hot or cold for longer than they would in a standard plastic bottle.

If you take your thermos flask to the local coffee shop and ask them to fill it up instead of having your drink served in a disposable coffee cup with plastic lid then you will be reducing the amount of landfill and waste material which gets produced from these establishments. Win win in our books! Why ‘Thermos’? Slurping soup is great fun from the Milu – in fact, we’ve started using it at home because it keeps your minestrone piping hot, unlike a cold china bowl from the cupboard. Capacity: 1 litre (33.8oz) / Temperature test: 0 hrs 90°c, 90 mins 86.5°c, 4 hrs 81.6°c, 6 hrs 78.1°c, 8 hrs 74.7°c, 24 hrs 53.7°c / Plastic-free stainless steel and silicone construction / 18/8 food-grade stainless steel interior doesn’t retain or impart flavours / Integrated double-wall construction cup / Twist and pour cap with 360° pour-through design / Internal Thread Design for increased thermal performance / Durable Klean Coat finish. BUY NOW: KLEANKANTEEN.CO.UK This thermos flask is made of a combination of Stainless Steel, Polypropylene and Silicone, and the dimensions are an excellent 21.1 x 12 x 9.1 cm. It is sized extraordinarily well for solo hikers who are concerned about size and weight but still wish to carry a hot brew around to warm up with. In our opinion this is one of the best thermos flasks on the market today. Another advantage of stainless steel it that does not leave a metallic taste in the mouth or residual odours. However, it is always worth cleaning your flask thoroughly with hot soapy water between uses.This is definitely one of the best thermos flasks for solo users due to the size of 21.8cm x 6.5cm and weight of only 0.33kg. This is light! You can see that a thermos flask will be a great companion for any outdoor activity! Using a Thermos Flask is Environmentally Friendly The 18-8 flask is from the renowned brand Stanley. Stanley has been serving people since 1913 and this model is truly legendary. No other brand apart from Thermos themselves can boast such heritage. Dimensions

You probably wouldn't describe the scientific rigour as laboratory standard – but the tests did replicate the kind of environment you'd actually use these flasks in, either filling up your tea or coffee at the start of the day, or icing water. And the results were certainly interesting. While the cold water tended to record similar temperatures across products (with the exception of Klean Kanteen, which I'll get to), there was a significant degree of difference when it came to heat retention. My conclusion is that if you really care about keeping your caffeine hot, you should choose your insulated flask wisely. Available in a range of colours (we like the electric blue), the flask is highly suitable for camping trips and general travelling refreshments. Pouring is very easy due to the superb flexible handle fabricated from silicone. As we said before, vacuum insulation is important for keeping the heat energy inside your flask, and the Hydro Flask does this well. It is made of stainless steel that is extremely good for heat retention.

Other useful design features to look for include a wide mouth, which makes for easier cleaning and filling (especially if you want to add ice cubes to your flask). In addition, many larger flasks incorporate ‘twist and pour’ spouts, so you can pour from the flask without having to completely remove the stopper. An integrated cup is also useful. Smaller flasks often feature lid designs that allow on-the-go swigging or one-handed operation. It comes with two cups with proper handles, so it's a great tea flask. It works well for families and small groups, making 5 or so generous servings. The twist stopper has a cunning hidden compartment in which to store milk or sugar; which I liked. The temperature performance is excellent and compares favourably to the other top performers in the world of elite flasks. Your coffee will remain hot after 12 hours and your ice cubes will remain unmelted after a very decent 24 hours. So, you can still pour a chilled drink even after a long walk on a hot day. Part of this ability is due to the clever ‘honeycomb’ insulation used inside the Hydro Flask. It worked well for us! The Milu Thermo Food Flask is a bowl-shape flask (16 x 10 cm) that is not only useful for keeping your drinks hot/cold, but also certain types of liquid-based food. You can keep soup, rice, noodles, fruits and even baby food in this great flask. All parents know that it’s often a problem carrying baby food at the right temperature. The 450ml flask Milu is a great solution to the problem.