However, this is not always practical in terms of rucksack space, and you may not wish to spend 5-10 minutes in cold conditions to make a brew.

However, you’ll have to timeshare the cups if there’s more than two of you, or bring along a couple of extra lightweight mugs. Multi-wall insulation: Double-wall insulation creates a vacuumed layer, which is vital for keeping hot drinks hot and cold drinks cold. For instance, the cup is insulated with plastic, so our tea retained its heat without being too hot to hold. The temperature performance is excellent and compares favourably to the other top performers in the world of elite flasks. 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.

The lid is attached to the bottle by a durable strap which provides great grip and leverage for easily unscrewing, particularly with slippery or frozen hands. A much simpler alternative is to pack a thermos flask containing a pre-made drink in your backpack instead. Within its stainless steel construction is a copper lining, although there’s no metallic smell on opening. The specifications state that hot drinks will stay steamy up to eight hours, whilst cold ones will be cool for 12. Insulated cup: Good flasks also pay attention to the insulation of the detachable cup, if they have one.

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. The Okadi incorporates two cups as part of its sleek design – these come in very handy when you are sharing drinks with your family. The size you pick should be based on your individual needs, as well as the activities you might be doing while using it.

The lid of the Smardy is 100% leakproof and non-toxic and can act as a small cup, but isn’t the biggest on offer in this roundup.

The flask is wide enough to be used as an insulated lunchbox, too, but you would need to bring your own spoon. That may seem extravagant for a drinks container, but you will soon save much more on drinks and lunches.Key specs – Material: 18/8 stainless steel (not officially dishwasher-safe); Capacity: 470ml; Size: 14. Stews and soups stay very hot all day, while fruit and tubs of yoghurt stay cool all day – or fridge-cold if you include an ice pack in the flask.

We found that it is particularly effective for cold drinks, with ice cubes still being solid after a 30 hour test we performed. The iconic Stainless King™ range incorporates sleek, industrial styling, blending technology with heritage.It can’t match the Stanley Master for sheer insulating power (no flask can, to be honest) but it still does a great job of keeping cold drinks cold for a couple of days, and hot drinks piping hot all day. The Hydro Flask has a sturdy lid that engages well into the bottle neck and is thoroughly leak proof. We also love the classic Sigg handle, which doubles as a lever so you can open it using a stick if your hands are cold or dirty.