These days, whether I’m hiking or trail running or going for a single day trip or a multi-dayer, I don’t bother with water bottles anymore. Portable water filters are always my first choice.

I remember back when I walked around Wales on the coastal path and Offa’s Dyke, there were stretches when I’d be lugging litres on my back for miles. I also remember sneaking into one or two gardens to use people’s hoses. I’ll never go back to that now, not when I can have the convenience of a filter that can get rid of the nasty stuff while saving so much weight as well.

While there are loads of different variations out there these days, including pumps, straws and UV sterilisers, I’ve come to prefer squeezy bottle filters most – they’re just very, very convenient.

Last year Katadyn came up with the BeFree, and then Lifestraw released their own version called the Flex. I’ve been using both extensively, and I’ve had very contrasting experiences.

The 67g Katadyn BeFree, an ISPO Gold Award winner, uses a hollow fibre filter with 0.1 micron-wide holes that block out nasty bacteria and protozoa but allow clean water to pass straight through. A squeezy plastic Hydrapak bag is screwed onto the end of the filter so you can fill up and drink away when you need to.

“What is an issue is that its flow rate is much slower…”

I took this with me on a five-day hike along the Snowdonia Slate Trail during last summer’s heatwave and I didn’t feel any dehydration despite the 30 degree heat I experienced. I also came away with a digestion system still functioning smoothly thanks to it!

What impressed me most about it was the flow rate. By squeezing the bag gently, the water will squirt out easily, almost as if there’s no filter for it to get through. So you don’t need to suck, and that’s a massive bonus as it means you can decant clean water into another cup or pot when necessary – if you want to fill up another water bottle for instance.

The 90g Lifestraw Flex can also decant, but it’s slow in comparison to the BeFree. The filter involved here is a variation on the original Lifestraw, using a two-stage hollow fibre process to clear out bacteria and protozoa. It’s a fair bit longer than the Katadyn BeFree’s, making it just slightly less packable, but that’s not really an issue. What is an issue is that flow rate.