Stainless Steel Water Bottle, Insulated Travel Mug with Leakproof Cup Lid & Handle, 500ml Double Walled Vacuum Flask, Coffee Cup Drink Bottle Keep 12h Hot & Cold for Gym Home Office Outdoor, Blue My hot water was 93.6°C at 8:25pm, and I already had my suspicions, because the exterior was markedly hot compared to the others – a sure sign of heat escaping. At 8:25am it was 34.8°C – a significant temperature drop of 58.8°C after 12 hours. Unlike the other flasks, my cold water and cubes didn’t get colder – it got hotter. The marketing blurb says it keeps contents hot for 28 hours, or cold for 90 hours, which based on these results I can’t really see happening. 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.

How do Thermos flasks work? In short, they use a double walled construction, with the air removed from between these walls, forming a vacuum. Heat struggles to pass through the vacuum, meaning liquid stays at a roughly constant temperature. The Stanley Classic is the Daddy of all insulated flasks, and with good reason. My hot water was 84.6°C at 7:51pm, and at 7:51 am it was 70.8 °C – a temperature drop of a mere 13.8°C after 12 hours (far less than its competitors, as detailed below).The strong stainless steel unbreakable double wall insulated material ensures that the contents is kept cold or hot for hours. The design features a integrated screw and a push button top for easy pouring. The flask is light and convenient to carry and it's easy to clean as the material wipes and washes with little effort. My hot water was 95.4°C at 7:56pm, and at 7:56am it was 76.3°C. That’s a temperature drop of 19.1°C after 12 hours. Meanwhile, my cold water was 4.5°C at 11:10am, and 1.5°C at 11:10pm. Stanley Classic Legendary Bottle 1.9L / 2.0QT Hammertone Green - Stainless Steel Thermos Flask - BPA-free - Keeps 32 Hours Hot or Cold - Dishwasher Safe - Leak-proof Lid Serves As A Cup Red Paddle Co manufacture paddle boards, but now they’ve also launched a versatile equipment range, Red Original. The kit can be used by anyone (no paddling required) and their marine-grade stainless steel water bottle is cleverly designed. The higher quality steel means it doesn’t corrode like other metal drinks bottles, and can withstand the elements.

After Stanley, I found the Thermos – a brand which has become synonymous with insulated flasks – to come a close second in terms of heat retention. My hot water was 91.3°C at 8:36pm; at 8:36am it was 75.7°C – a temperature drop of 15.6°C after 12 hours (not that much more than the Stanley, and still piping hot enough for a decent brew). My cold water was 4.4°C at 11:13am, and as with the Stanley, 12 hours later it was even colder – at 1.7 °C.Vacuum Insulated Water Bottle】Thanks to the premium coated copper on the exterior of the inner wall contributes to added insulation, This vacuum insulated drink flask can keep hot for 12 hours or cold for 9+ hours, greatly protect the liquid compartment from the hot or cold outside, achieving in reducing temperature transmission in maximum