Thermal Flasks and Bottles

Thermal Flasks and Bottles FAQs

How does a thermal flask keep drinks hot for so long?

A thermal flask has a double stainless steel wall with a vacuum between the skins, which blocks heat transfer by conduction and convection, and a thin layer of copper reduces heat loss by radiation. The result is impressive: a half-litre flask can keep a drink warm for around 14 hours, and a one-litre for up to 28. If you only need cool water on a short outing, our plastic water bottles are lighter and simpler to carry.

What makes a thermal flask so effective at retaining heat?

A couple of tricks help a lot. Pre-warm the flask by filling it with hot water for five minutes, then tip that out and add your hot drink before sealing it. Fill it as full as you can, since a fuller flask holds temperature longer, and close the cap firmly. Pour boiling water over our dehydrated camping food, and the flask keeps the rest of your brew hot while the meal rehydrates.

Can a thermal flask be used for cold drinks, too?

It can; the same vacuum insulation that holds heat in also blocks external heat, so a flask keeps water icy or juice chilled through a hot day just as well as it holds coffee warm. Fill it with cold liquid and a little ice for the longest-lasting cooling performance. Carrying a larger volume of cold water hands-free on a hike, our camping water bladder sits flat in a pack with a hose to sip from.

What features make a thermal flask easy to use?

A quick-open lid you can operate with one hand, ideally with a lock to prevent it popping open in your bag, and an integrated filter for tea leaves or fruit make a flask much easier to use. A wide mouth is easier to fill and clean, and many are dishwasher safe. Smaller sizes and easy-to-use caps make our kids water bottles ideal for little hands.

Is a thermal flask suitable for everyday use?

Yes. A thermal flask is ideal for commuting, travelling, hiking, or long days outdoors, keeping hot drinks warm and cold drinks chilled for hours. Its leakproof design also makes it easy to carry in a backpack or work bag. If you don't need long-lasting insulation for hot drinks, our stainless steel camping water bottles are a practical everyday alternative for staying hydrated.