Primus Vacuum Bottle 350ml review: a stylish flask that performs well

Brighten up your drink stops with a colorful Primus Vacuum Bottle that ticks all the performance boxes

Primus Vacuum Bottle 350ml
(Image: © Jonathan Manning)

Advnture Verdict

A good-looking flask that performs its core function very well, keeping drinks hot or cold for many hours while you’re out on the trails.


  • +

    Fits in a rucksack side pocket

  • +

    Click-close stopper keeps in heat

  • +

    Stainless steel doesn’t pick up flavors

  • +

    Grippy powder-coated surface


  • -

    Narrow opening makes it harder to clean

  • -

    Fiddly to dismantle stopper for cleaning

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First impressions

The lively colors of the Primus Vacuum Bottle range of vacuum flasks make them an attractive addition to your outdoor kit cupboard.

The lid of the Primus Vacuum Bottle serves as a handy cup – although, as with most flasks, the volume is pretty small, especially if you’re accustomed to the giant beakers of high street coffee outlets.


RRP: £16.79 (UK) / €22 (EU)
Volume: 350ml / 11.8fl oz
Other available volumes: 500ml, 750ml, 1-litre
Weight (empty): 280g / 9.9oz
Height: 21cm / 8.3in
Lid-opening style: Click-close stopper
Colors: Pale Blue / Leaf Green / Black / Salmon Pink / Melon Pink

In the field

The bright colors of the Primus Vacuum Bottle range are not just a pretty face on a functional item of outdoor kit. Firstly, in bright yellow this flask is always easy to spot in my pack.

Secondly, the powder coating gives enough purchase that it’s possible to unscrew the lid without taking off your gloves, which is a massive bonus when the mercury plummets. Then it’s simply a question of pushing down the button in the centre of the stopper and pouring your drink.

This ‘sealed’ stopper does make it a little harder to assess how much drink is left in the flask – walkers will have to count the cupfuls they pour to keep track.

It’s not the neatest spout, either, and it is far from ideal if you fancy swigging cold drinks directly from the flask.

After use, the narrow opening makes cleaning the Primus Vacuum Bottle a little difficult, particularly if you take milk in your coffee or fill the flask with soup, although long brushes are available. The click-close button also disassembles for cleaning, but it’s far from obvious how to do this – I found soaking it for a while, before rinsing in boiling water, worked best.

On the plus side, the narrow top and sealed stopper does very effectively trap heat inside to keep drinks warmer for longer. During our testing process, boiling water in our flask had cooled only to 70°C after four hours, which is still way too hot to drink.

Jonathan Manning

After spending a decade as editor of Country Walking, the UK’s biggest-selling walking magazine, Jonathan moved to edit Outdoor Fitness magazine, adding adrenaline to his adventures and expeditions. He has hiked stages or completed all of the UK's national trails, but was once overtaken by three Smurfs, a cross-dressing Little Bo Peep, and a pair of Teletubbies on an ascent of Snowdon. (Turns out they were soldiers on a fundraising mission.)