Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Saturday, September 9, 2017

GEAR REVIEW: Katadyn BeFree Collapsible Water Filter Bottle

The BeFree collapsible water filter bottle at long last is the ideal ultralight water filtration system that I have been looking for. It’s very lightweight at 2 ounces, compact, effectively filters water to safe levels, has a fast flow rate, is easy to use, and it’s fairly inexpensive.

By Will Rietveld

Water is heavy, so I don’t want to carry any more than necessary. When I am backpacking in an area that I know will have water available at frequent intervals, I carry a small bottle and refill it often. The complication is water purification – how can I purify water quickly with the lightest technology?

Two of the lightweight solutions I have tested are: 1) the Sawyer Mini water filter on a small soda bottle, and 2) a wide mouth small soda bottle (e.g., a Gatoraid bottle) and a Steripen Freedom UV water purifier. Neither is ideal in terms of performance, light weight, and convenience. The Sawyer Mini filter has a slow flow rate and I get tired of sucking/squeezing hard to get water. The Steripen system only takes 45 seconds to treat a pint of water, and there is no wait time, but it relies on batteries and it failed me on one trip.

However, both systems are very lightweight, about 4 ounces total for the device and bottle. As far as convenience, the Sawyer Mini system needs to reside in a backpack side pocket, so it’s a bit hard to reach and replace; but the Steripen system can be carried in a shoulder pouch.

The new Katadyn BeFree filter bottle presents the opportunity to provide safe drinking water while reducing weight, with no wait time, a satisfying flow rate, and excellent convenience. Is it too good to be true?

When the Katadyn BeFree Water Filtration System became available, and I jumped on it. The whole system, bottle + filter, weighs only 2 ounces, and it has a low profile, so it works in a shoulder pouch. How does it perform for ultralight backpacking?

Specifications and Features

Katadyn (www.katadyn.com/)
BeFree Water Filtration System
Collapsible TPU bottle, hollow fiber water filter attached to cap
Tough collapsible bottle, fits any HydraPak  flask with a 43mm opening, flip cap on the drinking spout
Measured weight 2 oz, mfr specification 2 oz
$40, replacement filter $25


The 0.6 liter soft TPU flask used for the Katadyn BeFree is made by HydraPak. HydraPak has collapsible containers in several sizes and the BeFree filter + cap will fit any of them, as long as it’s a 43 millimeter opening. At present, that’s the only containers the BeFree will fit; it will not fit ordinary soda bottles, even those with a wider mouth.

The BeFree filtration system uses hollow fibers, like the Sawyer Mini and Squeeze water filters, and the specifications are similar: 0.1 micron absolute hollow-fiber water filter that is 99.99% effective for removing protozoa, including Giardia and Cryptosporidium, and 99.9999% effective for removing bacteria. The difference – and this is a BIG difference – is the BeFree has a much higher flow rate.

The process for using the BeFree is: remove the cap + filter, fill the bottle at any water source (preferably clear water), replace the cap + filter, then flip up a drink spout cover and drink. The claimed lifespan of the filter is 1000 liters, or 2000 fillings, but that depends on water quality.

Katadyn first introduced the BeFree in a 0.6 liter size, which I tested. However, when I first drafted this review I discovered that they subsequently introduced 1 liter (2.3 ounces/$45) and 3 liter (3.5 ounces/$60) versions of the BeFree, which deserved my attention.

Since my main interest is an ultralight water treatment system, I focused on and tested the 0.6 liter size. But then another issue came up: apparently the first lot of that bottle was undersized; a mistake had been made and the bottle was about 0.4 liter rather than 0.6 liter. So I had to back up and test the true 0.6 liter size so I could evaluate it. I also tested the 1 liter size to see how well it fits into a packing system, but did not test the 3-liter version.

Left to right: 1-liter, 0.6 liter, and the original "0.6 liter" BeFree water filtration bottles. The latter size was a production goof and is no longer available. It's 8.5 inches tall compared to the true 0.6 liter bottle's (center) height of 10.5 inches.

Field Testing

I tested the BeFree on several mountain day hikes and three backpacking trips.

The undersized 0.6 liter (actual volume is about 0.4 liter) BeFree is 8.5 inches tall and carries nicely in a lightweight shoulder pouch. To drink, I flip open the cap and drink while squeezing the bottle while still in the mesh pouch. This size bottle provides about two drinks before it needs to be refilled, so it needs to be refilled frequently, which is inconvenient.

The true 0.6 liter size is 10.5 inches tall, a bit tall for my 7-inch shoulder strap pocket (same height as the one in the previous photo), but it works with an added rubber band to secure the top. This size provides about three drinks per filling, so it goes longer between refills, about right. Note the replacement cap for the one I lost (see next photo).

When water is plentiful and frequent, as it often is in the mountains, the 0.6 liter BeFree is perfect to minimize water weight. It is easily and quickly refilled at any water source.

I truly love the high flow rate of the BeFree. Getting a drink of water is more like drinking it straight out of a bottle, very satisfying. I was once a loyal user of the Sawyer Mini water filter, which mounts on any volume soda bottle with a standard 28 mm opening. But I grew tired of having to suck + squeeze hard to get water. The slower flow rate was not very satisfying, especially in hot weather.

To clean the BeFree, simply remove the filter and swish it in clean water, or partially fill the bottle, replace the filter, and shake it. It cannot be backflushed like the Sawyer filters, thus the 1000 liter lifespan. The Sawyer filters are claimed to filter 1 million gallons if backflushed regularly and properly.

For camp water, I simply filtered water through the small BeFree into a larger lightweight flask. It required only a few minutes and worked fine for one person, but was a bit cumbersome to filter enough water for two people. Perhaps the 3-liter size would be more convenient for filtering camp water for two or more people.

The only issue I had with the BeFree is the plastic hinge on the cap over the drink spout gradually broke off from use, and was quickly lost. That was a problem because, without a cap, the bottle spills water when I bend over. If it does break off, the drink spout can be replaced by a standard 28 millimeter cap (see previous photo). Another issue with the BeFree is the tab to lift the drink spout cover is small and not very visible, so I have to hunt for it each time I want to take a drink. To remedy that issue I marked it with a permanent marker (not shown in the photo).


The BeFree 0.6 liter collapsible water filter bottle at long last is the ideal ultralight water filtration system that I have been looking for. It’s very lightweight at 2 ounces, compact, effectively filters water to safe levels, is fast and easy to use, there is no wait time, and it’s fairly inexpensive. The Sawyer Mini is less expensive, but it has its limitations, as explained above.

The system I used before the BeFree consisted of the Steripen Freedom (2.7 ounces), a gallon size ziplock bag for treating water, and a 1-liter Platypus flask and drink tube hydration system. The 6.1 ounce system was fast and easy. However, the BeFree bottle plus a 1-liter flask for camp water weighs just 3 ounces. The BeFree system meets my needs for a net savings of 3 ounces. An alternative for trail water is to use a 20-ounce Gatoraid bottle with the Steripen Freedom, but that adds a little more weight and the stiffer plastic bottle does not squeeze and deliver water as well as the TPU BeFree bottle.

One drawback is the BeFree is limited to HydraPak TPU flasks with a 43 millimeter opening. It would be nice to have a version that fits a wider mouth plastic bottle available for free, like a Gatoraid bottle. That would be functional, but it would not squeeze as easily to deliver filtered water as the HydraPak TPU bottles.

The 1-liter size BeFree filter bottle is flared at the bottom, so it does not fit in my shoulder pouch, and is too heavy to carry by that method. However, it can be carried in a hipbelt mounted pouch for easy access.


  1. Very helpful post:) Im looking for a bottle holder for my 600ml (true 600) befree. What brand of sholder pouch do you use in the picture with the undersized .6l ?

  2. It doesn't have a label on it; I believe its Mountain Laurel Designs.