Hands-free reservoirs have changed the way we plan trips, allowing for greater amounts of fluids to be taken by the stronger muscles of the body. As well as increasing loads, hydration systems also aid fluid intake with easy-to-access straws and valve controls. With a view to innovating further, Platypus have taken this novel product spec to a new level by creating a system designed to slow the freezing of fluids in cold temperatures and to maintain their enjoyable coolness on hot days.

The Platypus Insulator provides a simple solution. Using the trusted Big Zip SL Reservoir, Platypus have added an outer layer to help limit the rate of cooling and heating of water. The unit is reinforced by a Cordura exterior sheath to ensure the durability of the the soft insulation.

While the product works well in most situations, improvements could be made to ensure that the outer tube/straw is better insulated for colder temperatures. Outside the shell of a rucksack, the outer tube doesn’t benefit from the additional insulation that a backpack provides and so freezes at a greater rate. As long as you take water regularly this shouldn’t be a problem because the movement of water from the reservoir through the straw should prevent freezing.

To measure the overall effectiveness of the unit I filled my 2 litre Platypus Insulator with water at 20° Celsius and walked for five hours in -3° without experiencing any freezing (when taking sips at regular intervals). When filled with water at room temperature on warmer days (+ 25° Celsius), the Insulator maintained its temperature for 5 hours very well.

Depending on your level of tolerance in warmer temperatures, it’s worth considering that the Platypus insulator is over double the weight of a 2 litre Big Zip SL Reservoir; A 2 litre version of the Reservoir itself is 157 grams while a 2 litre version of Insulator (plus Reservoir) comes to 351 grams.

Equipped with the standard Big Zip SL’s taste-free lining and a bite valve cover, this product is well worth thinking about investing in for an added tier of functionality and comfort on adventures in mixed conditions.

Useful Information

• RRP £35
• Available from ultralightoutdoorgear.co.uk
• Weights (including insulator sheath) 1.8 litres – 338 grams;  2 litres – 351 grams; 3 litres – 366 grams