We dropped each flask five times from 90cm to mimic a dropped flask. Those with large dents that inhibited function or ability were rated low. Flasks are more 'smell prone' than 'stain prone' – none of the flasks we tested had any staining after cleaning, but some retained a faint coffee smell. Button-operated lids are more efficient to use than twist-and-pour stoppers – we found the button-operated lids to be more secure than the twist-and-pour stoppers. We hand-washed each flask with hot soapy water and let them air dry overnight, then ranked them on smell. We examined each flask and its pouring mechanism and attachments for faults. We penalised flasks that had faults affecting their usability.

Our flasks and travel mugs are available in a range of sizes, large enough to hold cups of tea and coffee, soups or any other foods or liquids you may want to keep warm throughout the day. With your new good-quality flask or travel mug, you can also save on the pennies by taking your own tea or coffee with you when you leave the house. Compared to buying your hot drinks on the go, there are big savings to be had! 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.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'. Textured coatings are useful – it’s a nice touch to have a handle on a drinks flask but generally, for a one-litre flask, it’s more useful to have a textured coating that provides grip. Many of us have experienced our hot drinks going cold after a short time or, even worse, finding they’ve spilled or leaked in your bag. However, with our great selection of flasks and travel mugs, those memories will now be a thing of the past! Say goodbye to leaky, lukewarm drinks and hello to secure, warming flasks.