3L/5L Pump Action Air Pot Flask with Vacuum Insulated, Safety Lock & Carry Handle for Drink, Tea & Coffee by Crystals® (3L Air Pot Flask)

Product Information

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. Since the American manufacturer, Thermos, came to fame, the term has become slang for vacuum-insulated flasks. Although the terms are largely interchangeable, the original scientific phrasing is 'vacuum flask'.

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 To get maximum performance from your flask, you should always pre-warm it before use. Fill it with boiling water and leave to stand for five minutes or so before emptying and refilling with your chosen brew – such as tea, coffee, soup or hot chocolate. Filling your flask right to the top will also help minimise heat loss. Temperature Test: Method 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.In terms of heat retention, it is excellent. 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. Pretty incredible.

We examined each flask and its pouring mechanism and attachments for faults. We penalised flasks that had faults affecting their usability.

Stanley Classic 25oz Bottle

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 Some thermos flasks use a cork or plug to seal the liquid in, but we really don’t feel this is an effective design. Our suggestion is to go with a screw cap and a clip-on outer cap which will double as a cup.

The Smardy flask is manufactured with high-quality stainless steel that makes it extremely durable and we are confident it will perform well over the long-term. It utilizes a silver coat in the vacuum portion of the flask which enhances heat retention.Key attributes: Leakproof, practical design enables one-handed drinking, wide mouth for easy filling and cleaning You can see that a thermos flask will be a great companion for any outdoor activity! Using a Thermos Flask is Environmentally Friendly None of the flasks leaked from the main body – however, some flasks can't be filled to their stated capacity without liquid coming out when you screw on the lid. Warranty: We always suggest buying a vacuum flask from a manufacturer who will offer a warranty of at least one year, and preferably more. A warranty acts as a safeguard for your flask against unexpected defects, and ensures that you won’t have to buy again if something goes wrong. If you’re planning on spending a wodge of cash on a flask, then go for the one with the warranty. Typical Heat Retention Times The downside of this approach is that a high capacity flask will be big and bulky. There’s no getting away from it. However, if you’re able to split your gear equally between all members of the team (e.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.

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. Key attributes: Very light, design enables one-handed drinking, wide mouth for easy filling and cleaning.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. For a group hike, you need to keep lots of liquid on board for everybody to get a cup. If this is your plan then you should buy a thermos which can hold lots of liquid for the whole squad. It is definitely more space efficient to use one big flask for the group rather than several small, individual flasks. If you think about it, the majority of a flask is wasted space and not actually used for carrying liquid – it is there for the heat insulation. Better to just carry one big flask. 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. 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.