And if you’re heading out there with a friend, even better, because there’s a second plastic ‘buddy cup’ hidden inside the larger metal one.

Using a flask is actually also a very responsible thing to do in terms of recycling – apparently 99. We liked the push button on the lid – push it in to drink from it, push it again to lock it and seal in heat. Starting with hot water at 95 ℃, you can expect it to drop to around 60 ℃ after 12 hours, 51 ℃ after 24 hours and 40 ℃ after 36 hours. Hydro Flask are a fashionable US company who have made reusable flasks and water bottles immensely cool over on the West Coast of America.

Finally, there’s an additional loop handle on top so it can easily be attached to bags or simply carried this way.

The dual-wall of the flask is made of lightweight stainless steel which is heat resistant and won’t allow heat to drain away too quickly. This fab lightweight flask is designed to survive anything, without messing with the temperature of its contents, keeping your brew comfortably hot for 12 hours. Some thermos flasks use a cork or plug to seal the liquid in, but we really don’t feel this is an effective design.This thermos flask is made of a combination of Stainless Steel, Polypropylene and Silicone, and the dimensions are an excellent 21. Not having to remove the full cap reduces the amount of heat that escapes when using it, so liquids stay hot for longer. 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 steel is food-grade 18/8 so didn’t retain any smell or flavour from a tremendously strong cup of tea or coffee. 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.

When your hands are cold and you need a warm brew, you simply press down the blue switch to the ‘open’ position and you can immediately pour. A solid performer in testing, SHO’s food flask kept water chilled for the advertised 20 hours and even managed to keep a portion of ice cream very cold, albeit a little melted, for the same period of time. 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. The Okadi incorporates two cups as part of its sleek design – these come in very handy when you are sharing drinks with your family. 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.

g. one walker carries lunch, another carries the picnic blanket etc) then overall you will use less space than if you each carried smaller flasks. At the other end of the weight spectrum comes this gorgeous newcomer from Thermos, weighing in at barely more than 200g (before there’s anything in it, of course) and topped with a ‘direct drink’ spout that’s perfect for the train to work. For this article, we’ve picked out several flasks that excel at insulation, leak-proofness, durability and, of course, value for money.