BonDry Hydration Pack Dryer
Test Report by Richard Lyon

Male, 74 years old  
Height: 6' 3" [1.91 m]
Weight: 205 lb [(91 kg])
Email address: Montana DOT angler AT gmail DOT com
Home: Outside Bozeman, Montana USA, in the Bridger Mountains

I've been backpacking for half a century, most often in the Rockies. I do at least one weeklong trip every summer, and often take three-day trips.  I'm usually camping in alpine terrain, at altitudes 5000 to 10000 ft (1500 - 3000 m).  I prefer base camp backpacking, a long hike in with day trips from camp.  Though always looking for ways to reduce my pack weight, I still tend to include my favorite camp conveniences. I always sleep in a floored tent and like hot meals. Backcountry trips are often planned around skiing or ski touring in the winter or fishing opportunities in warmer weather.

Pertinent to this test, when backpacking, and almost always when day hiking, I carry water in a water bladder stashed in my pack. Bladder volume and additives turn on the weather conditions, length and difficulty of the hike, and my whim of the day. My only exception is when skiing or ski touring in temperatures consistently below 15 F. I have yet to find a bladder system in which the water won't freeze in the tube or at a valve at those temperatures.


Manufacturer: Fossil Outdoor Inc., fossiloutdoor.com
Measured weight: 1.25 oz/ 34 g
Listed dimensions: 17.5 x 3.5 in/45 x 9 cm
Measured dimensions: 17.4 x 3.5 in/44 x 9 cm
MSRP: $19.99 US
Useful life, listed: Six months, with a disclaimer that this was a pre-production estimate that has proven to be conservative.
Materials: "Sustainably sourced plant fibers and recycled plastic bottles."

The BonDry [pronounced bone dry] is intended for a neglected niche in hiking equipment - a simple and reliable means of drying a hydration reservoir. Simple it surely is. Step 1 - rinse the bladder to remove any extraneous matter such as electrolyte residue, wine, or anything else that isn't water. Step 2 - insert the BonDry into the mouth of the damp reservoir. Step 3 - Let it go to work. The proprietary material should wick the remaining water droplets to the top of the BonDry for evaporation. Can't get much easier than that. Testing will determine its effectiveness and reliability.

The manufacturer says that if one blows as much water as possible from the tube into the reservoir. BonDry will "usually do a pretty good job" of wicking out the droplets remaining in the tube.

Drying time turns on humidity and the amount of the BonDry exposed to the air. 

On its website the manufacturer says the product is machine washable [cold water/delicate cycle recommended], but should only be washed when it's truly dirty, such as when it's picked up residue from the bladder or has been dropped in the dirt. The process of wicking and evaporation should clean the product adequately.

                                                                                                    TRYING IT OUT

After a hike yesterday I took the Osprey 3L reservoir from my pack, rinsed it out, and inserted the BonDry. In the dry air of the Northern Rockies the bladder was almost dry in about 2.5 hours in the shade at a temperature of about 80 F [27 C], and completely dry the next morning. That's quite satisfactory for my purposes; I don't plan on taking the BonDry with me on overnight or longer trips. I'll wait until I return home to dry the bladder out.

An obvious limitation of the BonDry is its use for water bladders with a small cap - too small to cram the product into. I own several of these. The manufacturer's FAQ page has some cryptic instructions for capped bladders, but they don't work on an opening the size of a soda bottle's.

LONG TERM REPORT - December 15, 2020

Good news - I have very little to add to my Initial Report observations. After a six-day backpack in the Absaroka-Beartooth Wilderness, Montana, and Yellowstone national Park, Wyoming in late August-early September, I used the BonDry to dry out the 3L reservoir that I carried on the hike. As before the inside of the reservoir was, well, bone-dry the next morning. Before inserting the product into the reservoir I blew into the hose to force as much residual water into the body of the bladder. While a few drops remained in the hose the next morning, the BonDry had captured most of what had remained.

We had a lovely and extended Indian Summer in the Northern Rockies, with clear weather and daytime temperatures in the 70-80 F [21-27 C] range and low humidity. Ideal day hiking weather. I've tried to take full advantage, with at least a dozen day hikes and fishing days from mid-September to mid-October. After each outing I dried the water reservoir using the BonDry in my garage, and each time the reservoir was completely dry the next morning.

I may have found a way to use the BonDry on water containers with pop bottle-sized caps. The FAQ page on Fossil Outdoors website has directions for use on bisected bladders - cut the BonDry up the seam in the center with scissors, leaving something that looks roughly like a pair of trousers. I can then twist one "leg" and insert it into the reservoir. Fossil Outdoors acknowledges that this isn't perfect, and hints that a separate product may be on the drawing board. However this approach has worked for me, and I didn't notice any diminished utility when later using the bisected BonDry on the 3L bladder.

On my most recent day hike I added an electrolyte tablet to the water in the 3L bladder. The BonDry dried the inside as usual, but a bit of sandy residue remained. So I filled the bladder halfway with water and shook it vigorously, then drained it. I repeated that process, then inserted the BonDry, which performed its intended duties. Bear in mind that BonDry is a dehydrator, not a scrubber or a cleaner. I don't use my 3L reservoir for anything but water or electrolyte-spiked water. Other liquids [i e, wine or spirits] go into a separate container. I haven't used the BonDry on that container.

Fossil Outdoors says that the BonDry is machine-washable on a cold water/delicate cycle, noting that detergent may leave a detectable residue. I haven't tried this, but may do so when snow and winter end my usage of a water bladder. I have given the BonDry a thorough rinse in cold water after each use.

                                                                                                                                     SUMMARY and ACKNOWLEDGMENT

The BonDry is a niche product, and in my opinion a very useful addition to my gear closet. It's simple, easy to use, and works as advertised. Having it has prompted me to pay attention to regular drying of my water containers, something of obvious yet often overlooked sanitary benefit. I'm hoping that Fossil Outdoor succeeds in making the BonDry a standard product for water bladder users.

My Test Report ends here, with thanks to BackpackGearTest.org and Fossil Outdoors for the opportunity.