Which high-tech bottle keeps water chilled the longest?

WE’RE told to stay hydrated for the sake of our health, mental clarity and skin, but the plastic bottles we used to carry around are now considered an environmental faux pas.

The answer? A reusable, eco-friendly water bottle, with the added advantage of being insulated to cool your drink for longer — some even claim to keep water cold for 24 hours. But which should you buy?

We tested popular insulated bottles by filling them with fridge-chilled water, then taking the temperature over 24 hours.

We also looked at whether the mouths of the bottles were big enough to get ice cubes into, how much each bottle weighed empty, and how much water it held. Corkcicle Canteen Triple Insulated Flask, €28, cuckooland.com Weighs: 396g. Holds: 470ml (also available in 235ml and 710ml) AVAILABLE in a range of colours (main picture), this stainless steel flask looks more like a posh cocktail shaker. A rubber grip on the bottom means it’s non-slip and it comes with a plastic screw-on lid. Needs hand-washing. Can you fit in an ice cube? Yes Temperature increase after: 4 hours: 2c; 8 hours: 3.8c; 24 hours: 9c — taking it to 17c, which is impressive, since an uninsulated ‘control bottle’ reached 25c over 24 hours.

Verdict: A mid-range performer — and the heaviest of all so not ideal if you’re trekking miles. But it would look good holding chilled drinks at picnics. Bobble Insulate (right), €26.67, harveynichols.com Weighs: 290g. Holds: 442ml COMES in a range of designs. The screw-on lid has a built-in ring handle, meaning it’s easier to open and can be attached to things using a carabiner clip. Hand-washing is recommended to protect the pattern.

Ice cube? Yes Temperature: 4 hours: 1.8c; 8 hours: 3.6c; 24 hours: 8.5c Verdict: Sleek and sporty, perfect for walkers wanting a basic bottle to clip to a rucksack. Klean Kanteen Insulated Wide Bottle (below right), €32.95, earthmother.ie Weighs: 372g. Holds: 592ml (also 355ml and 473ml) THE top of this bottle, which claims to keep drinks cold for 48 hours, comes off entirely for filling, and has a ‘leakproof’ cap — you twist the disc on top of the bottle and drink through an opening. It makes on-the-go drinking easier, but also means you have to dismantle the lid into five parts to wash thoroughly (dishwasher safe, although they suggest handwashing the bottle).

Ice cube? Yes Temperature: 4 hours: 2c; 8 hours: 3.8c; 24 hours: 9.1c Verdict: Big but not that clever, it might struggle with its claim to stay cold for 48 hours. The lid is useful, but there are better, cheaper options. Thermos Super Light Direct Drink Flask, €25.60, thermosonline.co.uk Weighs: 210g. Holds: 470ml A MODERN flask in rose gold or black with a push button lid and locking catch. Fiveyear guarantee, dishwasher safe and lightest of them all. Ice cube? Yes Temperature: 4 hours: 1.7c; 8 hours: 3.1c; 24 hours: 7.8c

Verdict: Overall winner: second for insulation, it wins for being dishwasher safe, big enough to get ice cubes in, having a handy flip lid, and being the lightest. Chillys €30, chillysbottles.com Weighs: 288g. Holds: 500ml (also 260ml and 740ml) COMES in a range of designs, all with a classic screw-on lid, none dishwasher safe.

Ice cube? No Temperature: 4 hours: 1.4c; 8 hours: 2.9c; 24 hours: 7.3c Verdict: Excellent. If you want a basic bottle to keep water cool, this is the one. Kept water coldest. S’well water bottle, €43, amara.com Weighs: 308g. Holds: 500ml (also 260ml and 740ml) SOLD by swanky gyms, the

S’well bottle comes in a huge range of Instagram-worthy designs. Screw-on metal lid and has to be handwashed.

Ice cube? No

Temperature: 4 hours: 2.2c; 8 hours: 4.1c; 24 hours: 9.6c

Verdict: For the most expensive bottle to come third from bottom was really disappointing. Despite the celeb endorsement, this is a ‘don’t buy’. Hydro Flask, €31, 53degreesnorth.ie Weighs: 334g. Holds: 620ml (also 530ml and 710ml) COMES with interchangeable lids — standard screw top with a hook, or sport cap with a handsfree nozzle. Hand-wash only.

Ice cube? Yes Temperature: 4 hours: 2.3c; 8 hours: 4.5c; 24 hours: 10.2c Verdict: Looks good, but at this price it has to perform — and it came second from bottom. SIGG Hot & Cold One (left), €29.95, sigg.com Weighs: 332g. Holds: 500ml COMES in a rainbow of colours, with non-slip base, tea strainer and a flip-up top. Not dishwasher safe.

Ice cube? Yes Temperature: 4 hours: 2.1c; 8 hours: 3.9c; 24 hours: 9.0c Verdict: Unless you really want a tea strainer, go for the lighter, machine-washable Thermos at a similar price. BeMo Stainless Steel Bottle, €7.80, amazon.co.uk Weighs: 338g. Holds: 500ml THE cheapest bottle in our test comes in peach, blue or black with the slightly cheesy slogan ‘Be You’ on it. It’s a fraction of the price of many of the others.

Ice cube? No Temperature: 4 hours: 2.4c; 8 hours: 4.6c; 24 hours: 10.4c

Verdict: Cheap and it shows. The worst at keeping water cold and online reviews suggest even this worsens over time.