Friday, January 14, 2022
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Harrier Soft Flask Review

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Lucy Bird
Lucy Bird is a teacher and mum to three teenagers. She started running to build strength and fitness (and to escape the horrors of bath time when the children were little!). She became increasingly passionate about running and takes part in events of all types, but has found that her forte and joy lies in endurance over speed so race distances have been getting longer and more trail oriented. She is excited to be tackling her first ultramarathon this autumn having completed several standalone marathons and many triathlons up to Ironman distance over the past few years.

A good soft flask is a handy piece of kit for the long-distance runner, offering a simple lightweight solution for drinking on the move. Our reviewer tests this Harrier 500ml Soft Flask with Long Straw, from a new start-up company. 

This article contains affiliate links that help to support Run Deep.

Super speedy summary

I have been testing the Harrier soft flasks with a long straw  for a little while now. I’ve been unequivocally delighted with their quality and performance.

Available only through the Harrier website and they are a breath of fresh air in the running accessories department. They offer high quality and excellent value for money.

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These flasks cost £10-£11 each and perform as well as some I’ve had that are twice the price. I would recommend anyone give them a go, and also to take a look at the other products being launched by Harrier.

Harrier running soft flask 500ml
Clear volume markings on the rear of the flask

About Harrier

I was really excited to review these BPA-free soft flasks from Harrier. Harrier is a new start-up from Kate Mackenzie, an experienced and enthusiastic trail runner. She found that, while high-quality running accessories are available, they come with a matching price tag. The cheaper alternatives can be lower than ideal quality. Kate found this frustrating, so she set about researching and sourcing a select range of accessories she felt happy to put her name to.

Harrier produces a range of flasks: a regular 500ml with a bite valve; 500ml longer thin bite valve flasks (ideal for the front pockets of slimmer race vests); and the product I tested, a 500ml soft flask with a long straw. The flasks are available in a wide range of colours too. This not only means you can have your flask match your kit, but it actually makes sense for long races. You might want a different fluid in different flasks. Energy drink in yellow and water in blue, for example. After several hours out on the trail, this kind of distinction really appeals.

I have to admit to having a whole box full of different soft flasks. This isn’t because I have some kind of BPA-free plastic fetish, but simply because I have never found a flask that works. Some are too big, some too small, some leak and lots of them it’s just really hard to get the liquid out. I loved following the story of Harrier from its inception, so was keen to give them a go.

Harrier running soft flask 500ml
Harrier 500ml Soft Flask with long straw

How the soft flask performed

It starts well – the flasks are easy to fill. While soft, so they will collapse and scrumple up as you drink from them, they are sturdy enough to fill without wobbling. The lid screws on really easily and securely, which bodes well for mid-race refills. Refreshingly, there was no initial plasticky taste either, which is quite unusual. The 500ml long straw flasks slotted easily into my Ultimate Direction race vest and were at the perfect height for me to fasten the bungee across the top.

Harrier running soft flask 500ml in Ultimate Direction vest
Full flask at the beginning of the run

I tend not to drink much when running, as it can be difficult to access the flasks that don’t have a long straw without contorting myself. Not a good look and asking for trouble when running on uneven ground!

Long straw flasks can have two issues: it’s hard work sucking the water out, and/or you get poked in the face by the straw. No such problems with this Harrier flask. I drank with ease and there are no fiddly bits to slide up to get access to the water. I simply bit and sucked, and water arrived in my mouth.

Another minor miracle happened on this first testing of the Harrier soft flask; I got to the end of the bottle and actually ran out of water. It was only when the water was nearly finished did I have to squeeze the flask a bit to push the last few drops up. Often I’m ‘milking’ a flask for ages to try and get the water out.

Final thoughts on the soft flask

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It was a tremendously positive experience using the . By now I was really confident about the quality of the flasks and was not surprised that cleaning and drying them was just as easy. They stayed open while drying so no water remained inside.

In short, the Harrier soft flask is a great buy. £10 is a fantastic price for a well-made, robust and reliable soft flask that does exactly what it’s supposed to do: provide you with an efficient means of getting fluids down you while out enjoying your run. I now want them in every colour!

Harrier soft flask in use
Happy runner with my Harrier soft flask


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