Heat and cold retention is exemplary, with the Thermos lasting well over 24 hours for both. We found that it is particularly effective for cold drinks, with ice cubes still being solid after a 30 hour test we performed. Thermos have obviously squeezed out all routes for heat to get into the inner chamber of the flask. You can see that a thermos flask will be a great companion for any outdoor activity! Using a Thermos Flask is Environmentally Friendly 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!

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. The best thermos flasks can keep liquids hot or cold for a long time – over 12 hours in some cases. Look for a two-layer construction with an intermediate vacuum layer. This prevents heat loss by convection and conduction. You can leave your house with a full bottle of coffee on Friday evening and can have a nice walk with a cup of hot coffee on your weekend destination even on Saturday evening! You will definitely get a duration of 24 hours, and this model performs equally well for hot and cold temperature contents. In Use This flask has a familiar design with a classic ‘pop’ stopper that makes for easy pouring. With cheap, inferior flasks these are often prone to leaking but with this Outwell version the component seems well-made and reliable. It certainly didn’t leak on test. It’s a simple, inexpensive flask that makes use of a classic tried and tested design. The wide mouth makes the flask easy to fill and clean, while the cup’s plastic liner ensures you won’t burn your mouth. On the other hand, it is fairly bulky for a 750ml flask, with a small cup compared to some other designs. The external finish is also a bit slippery and prone to scratching. Full Specifications Using a flask is actually also a very responsible thing to do in terms of recycling – apparently 99.75% of disposable coffee cups are not recycled!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! Capacity: 500ml / Temperature test: 0 hrs 90°c, 90 mins 89.3°c, 4 hrs 82.8°c, 6 hrs 79.2°c, 8 hrs 75.3°c, 24 hrs 50.9°c / Stainless steel interior and exterior / Cool-touch, no-slip finish / Protective silicone rings for ultimate durability / Two part stopper for smooth pouring. BUY NOW: THERMOS.CO.UK As we said before, the Milu is more bowl-shaped and can easily be eaten from directly. The 6.6cm wide opening is extremely convenient for easy filling and eating as well. 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. 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!

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. That being said, we found that performance was not quite as good as a dedicated drinks flask – the Milu will keep your hot drinks hot for six hours and the cold ones for 10 hours. Like almost any decent bit of outdoor kit, a good vacuum flask should also be robust and durable. All the flasks we tested are made of high-quality 18/8 food-grade stainless steel that resists dents, dings and scratches. The trade-off with steel flasks is that they can be heavy, although modern designs are shaving weight all the time, and in some cases, they now weigh little more than a standard plastic drinks bottle.All materials on the Stanley are very robust and have a quality utilitarian feel to them. You can be assured that the food-grade stainless steel used on the Stanley won’t give a metallic taste to your drinks at all, but offers excellent heat retention. A range of scientific research has shown that BPA can seep into food or beverages and potentially cause a range of issues for the brains of fetuses, infants and children. Additional research suggests a possible link between BPA and increased blood pressure.

Some thermos flasks are designed to be handily-sized for solo use on hikes and outdoor adventures. Others are larger for bigger groups or car and campervan travel. Choose wisely, or get a couple for different activities.Thermos should just rename their 1 litre ‘Light and Compact’ vacuum flask as “The Daddy” because it effortlessly delivers everything you would expect from the company who developed the vacuum flask as we know it today from Sir James Dewar’s original prototype in 1904.

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

The Thermos has dimensions of 31 x 8 x 8 cm and weighs only 515g – a great size for a day hike. A 1 litre capacity is about the optimum in our view – enough to comfortably serve two people with hot or cold drinks throughout the day without being too much of an impediment to carry.