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Reviews > Hydration Systems > Bladders > Platypus Insulator Hydration System > Test Report by Hollis Easter

Platypus Insulator - Hydration Bladder
Test Series by Hollis Easter
Initial Report - 19 November 2008
Field Report - 6 February 2009
Long-Term Report - 5 April 2009

The Platypus Insulator is a hydration system, intended for very hot or very cold weather, that comprises a Platypus Big Zip SL bladder and an insulation system to protect the bladder, tube, and bite valve.

Quick navigation links:
Platypus Insulator with size comparison

Reviewer Information:

The author
The author

Name: Hollis Easter
Age: 28
Gender: Male
Height: 6'0" (1.8 m)
Weight: 205 lb (93 kg)
Email address: backpackgeartest[a@t)holliseaster(dah.t]com
City, State, Country: Potsdam, New York, USA
Backpacking Background: I started hiking as a child in the Adirondack Mountains of New York. As a teenager, I hiked my way to an Eagle Scout award. I love winter climbing, and long days through rough terrain abound. The peaks have become my year-round friends. I hope to return to multi-day backpacking.

I am a midweight backpacker: I don't carry unnecessary gear, but neither do I cut the edges from my maps. I hike in all seasons, at altitudes from sea level to 5,300 ft (1,600 m), and in temperatures from -30 F (-34 C) to 100 F (38 C).

Product Information:

Bite valve
Bite valve

Manufacturer: Cascade Designs, Inc.
Year of manufacture: 2008
Size tested: 100 fl oz (3.0 l), also available in 60 fl oz (1.8 l) and 70 fl oz (2.0 l) sizes.
Listed dimensions (web site): 18.75 in x 7.75 in (47.5 cm x 19.5 cm)
Listed dimensions (hang tag): 21 in x 8 in (53 cm x 20 cm)
Measured dimensions (pack): 19 in x 8.5 in (48 cm x 22 cm)
Measured dimensions (drinking tube): 43 in (109 cm) long
Listed weight (web site): none
Listed weight (hang tag): 5.4 oz (152 g)
Measured weight: 13.2 oz (374 g)
Listed volume: 100 fl oz (3.0 l)
Measured volume: 104 fl oz (3.08 l)
MSRP: $42.95 US

Product features (from manufacturer's web site):

  • Provides all-season protection for water supply
  • Will fend off freezing temps or blazing sun for extended periods
  • Drink tube and bite valve insulators are included
  • Includes Platypus Big Zip SL reservoir, drink tube, and insulators for all parts
  • Features SlimeGuard anti-microbial treatment to keep water fresh and taste-free
  • D-Rings allow for attachment to kayak decks, backpacks, or even car seats for road trips
  • Reservoir is made without using BPA (bisphenol-A)

Initial Report - 19 November 2008:

Insulator from the back
Insulator from the back

The Platypus Insulator is Platypus's insulation system for its hydration reservoirs. It is designed to facilitate the use of a hydration reservoir (hereafter also known as "hydration bladder", "water bladder", etc.) in very hot or very cold conditions. My interest in it comes primarily from its contention that it can fend off freezing temperatures for extended periods of time.

At first glance, the Platypus Insulator looks more like a kayaking deck bag than like a hydration system. The familiar plastic sack is nowhere to be seen, and all is sleek and black.

I'll start with the bite valve. The Insulator includes a standard Platypus bite valve, but it's tucked inside a blue rubber cap. The cap snaps into place around the bite valve, and is retained in place by a keeper strap leading to a rubber piece behind the valve. There's a flange at the tip of the cap, presumably to make it easier to grasp. It has a hole in it, whose purpose is unknown to me.

I find the cap relatively easy to open, although it's easiest to do with two hands: one holding the drinking tube, the other squeezing the cap to open it. The cap is a little bit more difficult to adjust with gloves on, but I've managed it. I haven't been able to get the cap or bite valve off the drinking tube; I'm not clear on whether it's possible to remove them for cleaning.

Next up is a flexible blue plastic drinking tube. This is sheathed entirely in a black foam rubber tube, which fits somewhat loosely. The insulation tube can be snugged over the base of the bite valve's cap, which seems to provide a fairly airtight fit. The foam insulation seems to be about 0.23 in (6 mm) thick. The insulation is supple and seems not to impede the flexibility of the drinking tube. I note that it presently carries a fairly strong rubber smell, like that of rubber tires in a shop.

Unplugging the drinking tube
Unplugging the drinking tube

The drinking tube connects to the reservoir through a clever rotating plug-in attachment point. The rotation feature is neat—I've had other bladders that frequently got twisted up and stopped working until they were untangled. The plug-in attachment is convenient, because it makes it much simpler to remove the bladder from the insulation pack. I just press a grey button atop the plug-in assembly, and the drinking tube pops out. The bladder remains watertight even when the drinking tube is disconnected, which makes filling the bladder easier: I no longer need to worry about dragging my bite valve through dirt or contaminated water.

The insulation pack is made out of a black synthetic material with a raised diamond pattern. I'm guessing it's ripstop nylon, but Platypus doesn't say. The pack features three plastic D-rings as tether points: a pair on the sides near the top opening of the pack, and another at the base of the pack. They're held down with a rubberized fabric (possibly Hypalon) that is sturdily stitched to the pack, leaving the D-ring free to rotate.

Buckle closure
Buckle closure

There are two openings in the insulation pack: a small one, just the right size for the plug-in attachment, near the base; and a larger folded opening at the top of the pack, for removing the water bladder. This entry flap is bound with bias tape and secured with a side-release plastic buckle.

The insulation pack appears to be a three-layered construction: an outer shell of ripstop material, a sandwiched layer of what feels like corrugated foam, and an inner liner of taffeta. I don't have a micrometer, so I can't get a reliable measurement for the insulation's thickness, but it seems a bit thinner than the drinking tube's insulation.

Behind the "front" of the insulation pack lurks a sturdily-stitched handle, made of webbing sealed with heat-shrink tubing. It fits my hand easily, and feels pleasant. There's a small grommet at the base of the insulation pack, which I assume is to allow condensation to escape.

Inside the insulation pack is a standard Platypus Big Zip SL hydration bladder. I believe the SL stands for "Slide Lock", a reference to the bladder's zipper closure. The bladder is made from a translucent plastic with a slightly sticky feel. It features markings along one side in 15 fl oz (0.5 l) increments, up to the maximum of 100 fl oz (3.0 l). There's room for some more water after the maximum marking.

At the top of the bladder is a blue plastic closure and handle. It slides off somewhat stiffly, revealing the plastic zipper beneath. I note that the zipper contains two sets of interlocking tracks, presumably to increase the zipper's strength. The blue plastic closure is a bit difficult to slide off; I was worried that I would rip the bladder the first time I opened it. It seems not to be a problem, though. The bladder is labeled "Slide shut to secure, invert to test", which I presume means that I should flip the whole thing upside-down after filling to see if it's properly closed.

There's a subtle touch here: the blue closure has a pair of "fingers" that press against the hydration bladder when they're interlocked. These fingers close the bladder's zipper automatically. I tested them and they're capable of closing up a completely open bag. The blue closure fits onto a ridge on the zipper, meaning that it's difficult (impossible?) to replace incorrectly. Nice!

It seems that the blue plastic slider clip is important to the system; it's affixed to the bladder with a short elastic keeper line.

Opening the slider
Opening the slider


During the Initial Report period, I used the Insulator for one day of field use. I'll be interested to see whether I can learn to use the Insulator effectively.

I like the fact that the plug-in attachment point for the drinking tube rotates easily, which allows the drinking tube to exit the bladder at any angle. Presumably this means I could stow the Insulator in any position in my pack. Given that it's a big hydration system, this is valuable.

Platypus didn't include a hose clip with the Insulator. With my other hydration system, I run the drinking tube through a D-ring on my backpack's shoulder strap. However, the Insulator's drinking tube is far too wide to fit through: it's .87 in (2.2 cm) in diameter. I took a small piece of blue polyester ribbon (such as is used for wrapping gifts) and made a new keeper loop for the tube. I tied it through the D-ring attachment on my pack using a tape knot, and hid the knot behind the D-ring. Problem solved!

Platypus Big Zip SL
Platypus Big Zip SL

No instructions of any kind were included. This left me somewhat confused as to how to properly care for and clean the Insulator and Big Zip SL. I was also unsure about the proper way to open the reservoir. Trial and error showed me how to do it, but a bit of instruction would be good. Do I need to lubricate the slider, zipper, or the O-ring on the plug-in attachment? I have no idea.

The Platypus web site is helpful but I found it somewhat unintuitive. There are no care or use guidelines for the Insulator system, and the care instructions for the Big Zip SL are not linked from either the Insulator or the Big Zip SL pages. I had to find the "FAQS" section at the bottom of the page's navigation menu for that.

The web site includes some discussion of how to keep the drinking tube from freezing in winter weather. I assumed these methods weren't necessary given the Insulator's insulation system; I was wrong. I've described my field experiences in a separate section below.

The bite valve is nice. I'm used to biting hard, but the Platypus bite valve requires only a gentle touch. When the tube remains un-frozen, it's easy to get quite a lot of water through the tube. I am not clear on whether it's possible to remove the bite valve to clean the drinking tube, and the Platypus web site doesn't tell me.

The slider was initially quite stiff, but it's loosened up somewhat as I've been opening and closing it. I like the way that it closes the zipper automatically.

I am very disappointed by the discrepancy between the advertised weight and the measured weight of the system. Small differences are normal, but the Insulator system weighs nearly three times what the hang tag says it does.

November 22, 2008: Phelps Mountain, NY

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
6 F (-14 C) up to 35 mph (56 kph) 4,161 feet (1,268 m) 70 F (21 C) 1 hour

We took the Klondike Notch trail from South Meadows, and then bushwhacked up the north side of Phelps from the Klondike Lean-To. Mileage from the GPS was 8.14 miles (13 km), and total ascent was 2,104 ft (641 m). It was very cold, with air temperatures of 6 F (-15 C) at the bottom of the hill, and reported wind gusts up to 35 mph (56 kph). Snow depths were about 6 in (15 cm).

The Platypus Insulator disappointed me on this trip. I put the bladder inside my pack (unsurprisingly, it didn't even come close to fitting in the hydration bladder sleeve) with its drinking tube running through the hydration slot in my Lowe Alpine Cholatse 35 day pack.

When I left home, the water in the bladder (inside the insulation pack) was 70 F (21 C). I took a sip shortly after starting the hike, and found that the bite valve had iced over, and that the tube was beginning to freeze. I drank a great deal of water to clear the icy bit. This proceeded every few minutes, getting progressively more difficult, until the tube finally froze solid at the one hour mark. No amount of sucking or blowing helped, nor did flexing the tube repeatedly to break up the ice jam. I ended up packing the bladder and tube into my pack and giving up.

This was nearly a disaster for me. Aside from drinking out of the huge zippered opening, there's no way to get water out of the Platypus bladder if the tube freezes up. I was worried that the bladder would slosh all over me if I tried drinking from the zipper—it certainly splashed me when I tried that maneuver at home. So I was left carrying a lot of water that I was hesitant to access for fear of spilling it and chilling myself.

The system, as I used it, failed me on that trip. I relied on it for something very important—hydration—and it let me down. It's possible that I failed to perform some necessary step, but no instructions were included with the system, and the Platypus website didn't lead me to believe that special techniques were needed with the Insulator. There are guidelines for the uninsulated Big Zip SL; I followed their instruction to sip frequently, and it didn't help. I drank more than 0.5 l (16 fl oz) in the first half hour, and the tube still froze.

I've hiked in much colder temperatures before without anything like the physical problems that arose on this trip. I got very cold, lost the ability to flex my fingers, and started displaying classic signs of both hypothermia and frostbite. If I hadn't caught the problem quickly, things could have gotten a lot worse. The only variable I see here was the attempt to use the hydration bladder. I was very lucky to have carried a backup water supply.

I'm going to keep using the Insulator, but my confidence has been shaken. I'll be carrying backup water supplies for a while, which will increase the weight and bulk of my pack. I was unable to learn from the Platypus web site whether it was safe to use boiling water in the Big Zip SL. The web site says it's safe to boil the bladder for cleaning purposes, but doesn't mention whether it's safe to drink the water afterwards. I wrote to the Cascade Designs people after my unsuccessful field experience to ask for help, and I received a quick and courteous reply from Nathan. I quote it here:

Dear Hollis,

Thank you for contacting Cascade Designs Inc.
Wow! It must have been really cold. Yes, Platypus can handle both freezing and boiling water without leaching of any chemicals. It is possible that that the heat could radiate through the material and burn you if it gets close to your skin. Also, if you were to have a leak it is possible that you could come into contact with the hot water. A couple other options are to blow warm air into the hose on occasion with your mouth or add some powdered sports drink to the water which will lower its freezing temperature.

I'm impressed by the speed of their reply, and the fact that they had useful ideas to share. I'll see whether it works to blow all the water out of the tube and into the bladder when I'm done sipping. If there's no water in the tube, it'll be less likely to freeze. This may be a pain since the drinking tube is long, but I'll try it.

It seems likely that there's a necessary skill set involved with the Insulator just as there is with many other sorts of gear. We'll see. I may be able to use the Insulator in the severe cold we get in the Adirondacks. I include this description of my failed attempt to make it clear that the system didn't work without adjustment, and that the lack of instructions was problematic.

The Platypus Insulator now feels like a challenge, and I'm looking forward to it on that basis. I hope to have positive results to report in two months; please check back and see!

Field Report - 6 February 2009

During this period, I used the Platypus Insulator for 5 days. All of them involved at least 10 hours outdoors in weather ranging from -19 F (-28 C) to 25 F (-4 C) not including wind chill.

As I expected, there was a learning curve involved with the Platypus Insulator. Now that I've learned to manage its weak points, the Insulator's strengths have begun to shine. The Insulator is hardly fool-proof, but one might question what business fools have in the backcountry in winter.

All my field experience in this period took place in the Adirondack Mountains of New York. All temperatures are as recorded in the parking lot unless otherwise specified.

November 29, 2008: Jenkins and Little Jenkins Mountains

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
<25 F (-4 C) up to 10 mph (16 kph) ~2,500 ft (760 m) 1:1 boiling and tap water did not freeze

We walked trail to the base of the peaks, then bushwhacked up the west side of Jenkins, down into the col between the two peaks, up Little Jenkins, and back out to the road. Total distance was about 9 miles (14 km), for a total ascent of 1,800 ft (550 m).

December 20, 2008: Ice Climbing in Cascade Pass

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
5 F (-15 C) up to 10 mph (16 kph) not measured 1:1 boiling and tap water did not freeze

I used the Insulator while ice climbing in Cascade Pass near Keene, New York. I left it in my pack on the ground while we top-roped water ice all day long. Total hiking distance was negligible.

January 10, 2009: Phelps Mountain

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
-19 F (-28 C) up to 5 mph (8 kph) 4,161 feet (1,268 m) 1:1 boiling and tap water did not freeze

I climbed Phelps again, this time by the trail, with a new partner. Total distance was 9 miles (15 km), with 1,982 ft (605 m) elevation gain. It was bitterly cold, and I spent a long time relatively unprotected on the summit treating a pair of inexperienced hikers for mild hypothermia. Amusing to me, given my previous climb (and experience) of Phelps this year. This time, I was armed with greater knowledge and a brand new Wilderness First Responder certification.

January 17, 2009: Mount Redfield

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
-18 F (-28 C) up to 10 mph (16 kph) 4,606 feet (1,403 m) 1:1 boiling and tap water 10 hours

I climbed Redfield from the Upper Works trailhead on a day that was nasty and often devoid of views, although we did see a very feisty pine marten. Total distance was 18 miles (29 km) of trail and bushwhack, with 2,900 ft (890 m) elevation gain.

January 24, 2008: Mount Marshall

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
-10 F (-23 C) gusting to 60 mph (97 kph) 4,360 feet (1,328 m) 1:1 boiling and tap water 9.5 hours

We attempted Marshall on a blustery day that was forecast for terrible weather. A front moved through, leaving us with an unexpectedly clear but gusty and cold day. A number of the hikers on the trip were underprepared, which left us turning around before reaching the summit. Total distance was 16 miles (26 km) of trail and bushwhack, with 3,400 ft (1,036 m) elevation gain. Wind chill was reported at -55 F (-48 C).


Marcy Dam with Wright's Angel Slides
Marcy Dam with Wright's Angel Slides

In my experience, the only hydration systems proof against freezing are insulated Thermos-brand bottles full of boiling liquids. Everything else will freeze in the course of a long day in the mountains. My experience with the Insulator bears out the assessment: everything freezes eventually.

After a while, what matters is the rate of freezing. A system that freezes in an hour is practically useless; one that freezes more slowly may still be useful.

We've had a pretty cold winter so far, and it's afforded me some good chances to test the limits of the Insulator's capabilities. I am satisfied with its performance. All winter gear involves trade-offs between function and weight. Could the Insulator be better insulated? Perhaps. But it seems to work reasonably well for me now that I've learned some tricks of the trade.

Chief among those tricks is the habit of always blowing air through the drinking tube immediately after taking a sip. Failure to do this causes a frozen hose, which is basically irreparable in the field. Blowing air into the hose will take me down to a bit below 0 F (-18 C) without many problems. A few tiny ice crystals may form in the bite valve, but I can easily crunch them apart with my teeth.

I may be frozen, but I still have water!
I may be frozen, but I still have water!

Once the temperature drops further, ice seems to form persistently in the bite valve, beyond my ability to break up with my teeth. I've cultivated the habit of walking with the bite valve tucked inside my slightly-unzipped jacket, keeping it near my armpit just outside my base layer garment. This works very well, and causes no problems.

Note well, though, that the bite valve has to be inside all the jackets I'm wearing, not just the outermost one. When walking across Lake Colden on the Mount Marshall trip, the winds were strong enough to repeatedly knock over hikers in front of me. I had to fully zip my insulated fleece and the hard shell atop it, and there was no way to keep the valve inside: the risk of frostbite was too high to permit an opening. Twenty minutes later, the valve had frozen solid, and it took a long time to re-warm it.

On Redfield and Marshall, the bladder eventually froze at the point where the bladder and the hose join, down inside my pack. Once this happens, no further tricks are useful. It might work to use a higher ratio of boiling water to tap water on days where it's going to be really cold, but I find the flavor of the boiled water quite unpalatable, so it's a toss-up. We'll see.

Filling the Insulator remains challenging, but I've developed a work-around. I leave the bladder inside the insulation pack, and hang the whole assembly by the pack's handle. Wrapping the insulated flap around my hand to protect from splashes, I then squeeze the ends of the zipper to hold it open while I pour. All my hikes during this period have been day hikes, so I've only tested this while hanging the pack on a kitchen hook.

I'm really enjoying the large capacity of this bladder. I'm carrying more water—3.5 L between the Insulator and my Thermos—than I'm used to, but I'm drinking it. I'm always dehydrated after a winter hike, but I think the large capacity and convenience of the Insulator have helped to stem the tide. I've never yet drunk the bladder dry, but I usually bring it back with about 0.5 L remaining. Rationing water is difficult with any hydration bladder. I'll be very impressed if some manufacturer comes up with a solution to that problem.

I said, in the Initial Report, that the Insulator system failed me the way I used it. I hoped that greater experience and experimentation might yield a modus operandi that would work even in New York's cold winters. I think I've found it. While the Platypus Insulator has limitations, so do the other hydration systems I've used. The convenience of drinking on-the-go looms large for me, as does the safety factor of avoiding spills. It's nice not to worry about soaking my mitts or dropping all my water by accident.

Long-Term Report - 5 April 2009:

Onward and upward!
Onward and upward!

During this period, I used the Platypus Insulator for six days of strenuous mountain climbing in the Adirondack Mountains of New York. Most of my backpacking trips during the period got cancelled due to poor weather or lack of companions (I don't backpack alone in the winter), so this report is predominantly based on long day trips in the mountains.

I find the Insulator to be a great addition to my winter climbing gear, and plan to continue using it. After some adjustment to my preparation style, I was able to use the Insulator to stay happily hydrated throughout my hikes.

February 21, 2009: Allen Mtn

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
0 F (-18 C) to 14 F (-10 C) up to 10 mph (16 kph) 4,340 feet (1,323 m) 1:1 boiling and tap water did not freeze

We climbed Allen from the East River Trailhead on a day forecast for clouds and snow. We found that, although the Opalescent River's bridge had been destroyed by vandals, we were able to cross safely on the still-frozen ice. From there, the trail winds across a valley with beautiful views of Cliff, Redfield, and Allen mountains. It departs onto a hard path that climbs a shoulder of Redfield before diverting to Skylight Brook. We then climbed, off-trail, up Allen Brook, which ascends 2,000 ft (610 m) in about 1.5 miles (2.4 km). We had fun going up the relatively steep slide near the summit. Our total distance was 19 miles (31 km), total climb was 3,400 ft (1,037 m), and hiking time was 11.25 hours. The snow was deep, our company was good, and the weather opened out into a beautifully clear day!

March 1, 2009: Algonquin, Boundary, and Iroquois Mtns

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
0 F (-18 C) to 15 F (-9 C) up to 10 mph (16 kph) 5,114 ft (1,559 m); 4,813 ft (1,467 m); 4,837 ft (1,474 m) 1:1 boiling and tap water did not freeze

We climbed Algonquin, Boundary, and Iroquois from Adirondack Loj on a day that boasted unexpectedly beautiful sunshine and low winds. These peaks are exposed to a localized jet stream that normally blasts them hard—winds of 60 mph (100 kph) are common—so we were thrilled to get a calm day. We spent at least an hour on the summit of Iroquois eating lunch and taking in the scenery, and more time on Algonquin. We'd planned on climbing Wright Peak later in the day, but decided instead to play around on a rock face we found. I scrambled to the top of what's probably a class 3 or 4 climb, which gave beautiful views of Algonquin and Wright. Our total mileage was about 11 miles (18 km), and my altimeter's accumulated elevation was about 5,300 ft (1,615 m).

March 9, 2009: Marcy, Skylight, and Gray Mtns

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
0 F (-18 C) to 15 F (-9 C) up to 60 mph (100 kph) 5,344 ft (1,629 m); 4,926 ft (1,501 m); 4,840 ft (1,475 m) 1:1 boiling and tap water did not freeze

We did a long day trip up into the high peaks, ascending the highest, fourth highest, and seventh highest peaks in New York. We started from Adirondack Loj and climbed via the Van Hoevenberg trail to Marcy, where we found whiteout conditions: wind, loaded with ice pellets, blowing hard enough to suspend my trekking poles horizontally when dangled from their straps. This was a far cry from the calm winds that were forecast! I got to practice my map-and-compass navigation to get us down off the summit of Marcy into the col called Four Corners. From there we ascended Skylight, discovering many spruce traps. On Skylight's summit, the wind was just as hard, but blowing from the southwest (it was blowing from the northeast on Marcy, a mile away). We descended to Four Corners and thence to Lake Tear of the Clouds, where we began our very steep bushwhack up to Gray Peak.

We had planned on returning via Marcy, but we all wanted to stay out of the wind if we could. So we descended via Feldspar Brook, then climbed along the Opalescent to Lake Arnold, after which we descended to Marcy Dam and hiked out the normal route. Our total mileage was 19.5 miles (31.4 km) in 13 hours, with an altimeter-measured climb of 8,845 ft (2,695 m).

Whiteout conditions on Marcy
Whiteout conditions on Marcy.
Notice Insulator hose tucked into the neck of the jacket.

March 14, 2009: Santanoni, Couchsachraga, and Panther Mtns

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
-5 F (-21 C) to 35 F (2 C) up to 10 mph (16 kph) 4,607 ft (1,404 m); 3,820 ft (1,164 m); 4,442 ft (1,353 m) 1:1 boiling and tap water did not freeze

We had an absolutely glorious day out in the Santanoni Range, widely renowned as some of the hardest peaks in the Adirondacks. We left the trail well below Bradley Pond, following a route that's alternately known as the Tahawus Club Trail, the New-Old Trail, or the Santanoni Express. It was a trail cut in the 1920s that climbs the southeastern shoulder of Santanoni Peak. Land acquisitions by a private paper company in the late 1920s made this trail illegal; only recently has it become a legal "trail" again.

The herd path was significantly overgrown, and it was serious bushwhacking much of the time. We spent quite a bit of time on routefinding. Lovely, though, with beautiful views opening out to the east. The rest of the high peaks really put on their finery for us: I was awestricken by some of the views.

After a steep and sustained climb to Santanoni, we bushwhacked along the ridge to a junction point called Times Square: a little clearing that'll hold about 15 tightly-packed hikers and marks the junction between the standard bushwhacks to Santanoni, Couchsachraga, and Panther peaks. We "climbed" Couchsachraga next, which was a somewhat dismal effort: a very long descent to a col, followed by steep climbs over several bumps to the Couchie summit. We were rewarded with beautiful and clear views when we got there, though!

Two of us still wanted to climb Panther, so we sped on ahead—got stuck behind some slower hikers returning to Times Square, but we made it in good order. We went over to Panther, tagged the summit (and enjoyed the views), and returned to Times Square to meet our friends. We spent a while deciphering herd paths between Times Square and Herald Square (another junction point), then found one leading down Panther Brook to Bradley Pond. Trail running downhill in snowshoes is a lot of fun, and we descended 1,100 ft (335 m) in about 20 minutes. Sure was quicker than going up! A lovely day, overall.

Our total distance was approximately 16 miles (26 km) in 11.5 hours. My altimeter measured our total climb as 6,835 ft (2,083 m).

March 21, 2009: Donaldson, Emmons, Donaldson, Seward, and Donaldson Mtns (overnight trip)

Temperature:Wind:Elevation:Water Temperature:Time to Freeze:
15 F (-9 C) to 40 F (4 C) up to 10 mph (16 kph) 4,140 ft (1,262 m); 4,040 ft (1,231 m); 4,361 ft (1,329 m) 1:1 boiling and tap water did not freeze

Several friends and I decided to take the last day of "official winter" to finish up one friend's quest to become a Winter 46er: someone who's climbed all the highest peaks in the Adirondacks between December 21st and March 21st. She's now done, and I'm exactly halfway.

None of the peaks in the Seward Range have trails, and the walking definitely runs the gamut from "herd path" to "wading through Christmas trees". An access gate was closed, which necessitated an extra 6.6 miles (10.6 km) of walking. We followed a road to the summer trailhead, then followed the Blueberry Foot Trail to an old logging road leading south toward Calkins Brook. From there, we ascended off-trail on a truly lovely herd path up Calkins Brook. The herd path leads almost to the summit of Donaldson Mtn, the central peak of the ridge. We climbed Donaldson, descended (a heartbreakingly long way in endless krummholz) to a col and then climbed Emmons, then retraced our steps to Donaldson. Then another heavy bushwhack over to Seward, replete with another long descent. Beautiful weather for my friend's winter finish! Then back into the col, back almost all the way up Donaldson, and down.

We camped out the night before hiking; the alarms went off at 3:45 to enable us to be hiking by 5:30. Our total distance for the hiking day was about 24 miles (38.6 km) in just over 13 hours. The altimeter measured 5,905 ft (1,800 m) of climb, not including the climb of Emmons (I left my pack on Donaldson).

It was a heck of a way to finish up the winter season and my test of the Insulator. Time to hang up the snowshoes for a while!


Well-hydrated and warm on Boundary Peak
Well-hydrated and warm on Boundary Peak

Water is life. I have hiking companions who drink very little and seem to feel fine; I guess I'm just cast from a different mold. If I don't drink enough water, my performance goes downhill in a big hurry. Hydration bladders are a real boon for me because they make it easier to drink frequently enough without needing to stop moving.

I've come to love the Platypus Insulator. Now that I've learned its tricks, I find that I can rely on it to keep me well hydrated all winter long. It's seen me through some of the hardest winter peaks in the Adirondacks, in some very cold weather. It's a good thing.

Since it's taken me several months of fiddling to develop the procedure I currently use, I'll share it in hopes that someone might profit by it.

Standard Operating Procedure (filling and setup):

  1. Remove hose, leaving bladder inside the insulation pack.
  2. Open slider and zip closure on bladder.
  3. Fold flap of the insulation pack back over my left hand, protecting it, while holding the whole assembly perpendicular to my chest.
  4. Press bladder against my chest with left hand, so that the zip closure bows open.
  5. Pour a bit of cold water into the bladder (about .5 liter).
  6. Pour boiling water into the bladder (somewhere between 1.5 and 2 liters; whatever's left after my morning oatmeal).
  7. Top off the bladder with cold water.
  8. Carefully press the air out of the bladder, then seal the zip closure. Slide the blue slider onto the bladder.
  9. Invert the whole assembly to check for leaks (none so far, knock on wood).
  10. Buckle the insulation pack closed.
  11. Install hose on bladder.
  12. Place Insulator in main compartment of backpack, and then carefully thread the drinking hose through the backpack's hydration port.
  13. Thread hose through ribbon attachment on my shoulder strap.
  14. Pull hose out of pack until the bite valve is able to touch the bottom of shoulder strap.

This method works pretty well, and it's a lot more intuitive than it looks. Leaving the bladder inside the insulation pack makes it easier to control while filling, and folding the pack back over my hand protects me from splashes.

Even with backpacking cookware, it's pretty easy to pour the boiling water into the bladder without spills. I managed it at 3:45 in the morning! The hardest part is that boiling water emits a great deal of steam in the frigid pre-dawn air, making proper aim a sometimes-tenuous proposition. Still, it can be managed with a modicum of care.

The little blue grosgrain ribbon that I tied onto my shoulder strap is still going strong. I'm pleased to report that it hasn't damaged the hose insulation, either.

I've ended up mixing cold water and boiling water in the bladder. Partly this is due to paranoia on my part: I'm wary of pouring boiling water into plastic (even though Cascade Designs reports that it's safe), and I also don't want a backpack full of boiling water if the bladder should accidentally burst. Mainly, though, it's that I find the taste of boiled water unappetizing, and don't like sipping really hot water without any flavoring. So I cool it a bit, and it works fine.

On colder days, I suspect that I now raise the proportion of boiling water somewhat. This happens automatically; I no longer measure the quantities as I did earlier in the test.

When I slept out overnight, I left the bladder filled with warm water but removed the hose. I initially hung it from a carabiner inside my hammock, but then took a teammate's offer of space in his SUV. The water was still liquid when I awoke.

Standard Operating Procedure (drinking and stowing):

  1. Drink from the bite valve. I often leave the bite valve in my mouth for several strides, to see if I want another sip.
  2. When finished, fill cheeks with air.
  3. Blow air through the bite valve until I hear bubbling inside the bladder. This only takes one mouthful of air.
  4. Close blue rubber cap over bite valve.
  5. Tuck bite valve and hose through the neck of my baselayer shirt, down as far as they'll go.
  6. Close any insulating/shell layers around neck and hose.

Reverse the process to get a drink. As above, this quickly becomes intuitive.

After a while, I got tired of worrying about the bite valve freezing up. Even though it rarely happened, it always provoked anxiety. After that one episode of serious dehydration early in the test, I never wanted to get that dehydrated again! And so the moments where the bite valve froze stressed me out, because I could imagine losing my water supply completely. I also worried about the integrity of the bite valve, because I sometimes had to bite it quite hard to break up ice inside it.

Hose safely stowed on Seward
Hose safely stowed on Seward

My solution is to always keep the bite valve and hose tucked against my skin underneath my base layer. I put out so much heat while hiking that I suspect they'll never freeze as long as I'm alive. Theoretically, this arrangement could be annoying when wearing lots of tightly-closed insulating layers, because I'd have to undo them to get access to my water. In practice, though, it hasn't been an issue. If it's very windy and I'm in an exposed position, I just wait a few minutes for a drink. It's rare to find really long stretches of completely exposed hiking in the Adirondacks—even on the bare summits, I can grab a windbreak behind some rocks.

A nice benefit of keeping the tube tucked away is that it doesn't snag on trees, and it never whacks into my hands. Definitely good!

I cannot over-emphasize the importance of blowing the air out of the hose after drinking. It's critical. This simple trick cleared up almost all of my serious issues with the Insulator. It soon becomes automatic.

A side note: there were a few times when I sucked on the bladder and felt an agonizing thing: air, rather than water. It's bad news to run out of water, especially when it's unexpected. What I learned, though, was that I still had plenty of water. It's just that when I blow air into the hose each time, some of it ends up inside the bladder. When the water level drops below the hose attachment point, I start getting air rather than water.

The first time I "ran out of water", I got home to discover a full liter of water remaining in the bladder. So it's possible to "lose" a surprisingly large quantity of liquid this way. Just keep sucking on the hose and eventually the liquid comes out. If I suck and air comes out, I have more water. If I suck and can't get anything to come out, I'm empty. Simple!

The Insulator has held up well. I can't see any damage to the hose insulation or bite valve; considering all the heavy bushwhacking I did this winter, I'm impressed. Once, on a very cold morning, the bite valve pulled off the end of the hose. Luckily, I caught this before any liquid spilled out, and I was able to re-insert the valve while in the field. Since then, I've noticed that the blue rubber cap is slightly more likely to pop open; to me, this is really minor. I haven't had any problems with leaks inside my pack, which is wonderful!

I don't know how much difference the insulation makes, because I didn't try it without the insulation. Too much was at stake on these hikes for me to risk losing my water supply. Scientifically, I can't prove the insulation matters. However, the Insulator works, and that's good enough for me.

I've left water in the bladder for a couple of weeks at a time by accident. Although I haven't tried to drink that water, the bladder was easy to rinse clean and use again. I didn't notice any odor or flavor to the water, which was a relief. I'm prepared to call Platypus's SlimeGuard anti-microbial treatment a big success, and it seems to stand up to repeated dousings in boiling water.


The Insulator served me well. Here I'm standing on Algonquin Peak, with Colden and Marcy in the background. Notice my little blue ribbon holder around the hose.
The Insulator served me well.
Here I'm standing on Algonquin Peak, with Colden and Marcy in the background.
Notice my little blue ribbon holder around the hose.

I was initially skeptical about the Insulator's ability to keep my water from freezing through the cold of a northern New York winter. Although my learning curve had some significant bumps on it, I've gotten to the point of being able to use the Insulator as a reliable hydration system even in very cold weather.

To me, the ease of drinking provided by a hydration system far outweighs the cost of a bit of extra care in handling. I stayed well hydrated all winter; although I always wanted plenty of water at the end of the day, I never felt the dehydration headaches and desperate thirst that I remember from previous years.

I didn't get the chance to test the Insulator in a hot climate, so I can't speak to its use in summer conditions. I plan to continue using the Big Zip SL bladder throughout my summer backpacking, but I will probably leave the insulation system at home, since I don't care that much about warm water in summer.

For winter, though, the Insulator is now on my permanent gear list. It's lighter than insulated polycarbonate bottles would be, it makes it easy to drink while hiking, and it doesn't freeze. It's a keeper.

  • Hydration bladder is usable all winter long!
  • Rotating plug-in attachment makes positioning the bladder easy
  • Holds more than the advertised quantity
  • Zipper seems solidly constructed and is waterproof
  • Bite valve is easy to bite and has a high flow rate
  • Customer service was responsive and helpful
  • Drinking tube freezes quickly if I'm careless
  • Nearly three times heavier than the quoted weight!
  • No clip was included for the drinking tube

I thank BackpackGearTest and Cascade Designs for allowing me to test the Platypus Insulator.

Read more reviews of Platypus Hydration gear
Read more gear reviews by Hollis Easter

Reviews > Hydration Systems > Bladders > Platypus Insulator Hydration System > Test Report by Hollis Easter

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