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Reviews > Water Treatment > Filters > Sawyer S1 Select Water Filter > Test Report by joe schaffer
Sawyer S1 Water Filter
NAME: Joe Schaffer
HOME: Bay Area, California USA
I enjoy California's central Sierras, camping every month with a goal to match my age in nights out each year. For comfort I lug tent, mattress, chair and such. Typical summer trips run 5-8 days; 40 lb (18 kg), about half food and water related; about 5 miles (8 km) per hiking day in the bright and sunny granite in and around Yosemite. I winter base camp most often at 6,000 to 7,000 ft (1,800 to 2,000 m); 2 to 3 nights; 80 lb (23 kg); a mile or so (1.6 km) on snowshoes and towing a sled.
Product: S1 Select Filter
Manufacturer: Sawyer Products, Inc.
Manufacturer description from website, packaging and included pamphlet:
Select S1 is a dual stage filter. Inside the silicone bottle is a foam filter that uses adsorption to remove chemicals and pesticides. The Micro Squeeze Filter on top removes standard pathogens along with any other sediment, particulate, and microplastics. Adsorption filtration is the process in which molecules adhere to the surface of the adsorbent foam membrane. This filtration and purification process, combined with 0.1 micron absolute filter ensures all particulate or pathogens above 0.1 microns are filtered out, including bacteria, protozoa, cysts, dirt and sediment.
Weight: 10 oz (280 g)
•0.1 Micron absolute filter
•Removes: 99.99999% of bacteria
99.9999% of protozoa and cysts
•Reduces: pesticides down to 0.01 parts per billion (400 times lower than EPA maximum recommended level
chemicals down to 0.5 parts per billion (up to 40 times lower than EPA recommended level)
•1,600 +- 20 oz (0.6 L) filter uses
Bottle when dry: 7 7/8 oz (224 g)
Filter element when dry: 1 5/8 oz (46 g)
All parts before any water: 11 oz (311 g)
Full bottle & filter: 2 lb 3 3/8 oz (1,010 g)
Bottle only when squeezed out w/out filter: 12 5/8 oz (360 g)
Bottle only when squeezed out w/filter: 14 7/8 oz (422 g)
Plunger: 1 oz (26 g)
Bottle length w/filter: 13 5/8 in (34.6 cm)
Bottle length w/o filter: 11 1/8 in (28.3 cm)
Bottle width: 2 1/2 x 2 1/2 in (64 x 64 mm)
Filter: 3 7/8 in x 1 1/2 in diameter (9.8 x 3.8 cm)
Plunger: 5 3/4 x 1 7/8 in (14.6 x 4.8 cm)
MSRP: on Amazon, US $89.95 claimed as MSRP; offered at US $79.99
S1 system includes the foam-filled flexible silicon bottle, filter, standard cap, flip cap, backflush plunger and bottle thread adapter.
The system provides treated water out of the bottle or into a receiving vessel. The process involves filling the bottle to the prescribed level; squeezing the bottle in an alternating motion for 10 seconds to work the water in and out of the foam; then squeezing the bottle to force water through the Micro Squeeze filter. The silicone bottle and the internal foam are flexible enough to 'wrap' the bottle up from the bottom in order to apply greatest squeezing force.
S1 offers two ways to backflush the filter. A provided plunger allows a powerful surge through the filter. The provided blue adapter allows the output end of the filter to screw onto a typical plastic bottle, and then squeezing the bottle pushes water through the filter. Clean water is required in both cases. The plunger does not interface tightly with the filter's output nipple and relies on contact pressure.
I have maybe the very earliest iteration of Sawyer inline filter and I like it. S1 is an innovative water treatment system. Haven't seen anything quite like it before. Initial take is that it's weight-competitive and since I do carry a trail bottle, the system effectively could take up no additional space as a replacement for my regular trail bottle.
Of course I took off the black (reducer) cap immediately because I look at a bottle and feel instantly compelled to peer inside, especially when there is in fact something in there! If a fellow is oriented toward reading directions, then it's clear not to do that. Having done it, the the advice is to re-establish the possibly now-damaged seal, with no instruction as to how that task might be accomplished. A further caution warns that a damaged or otherwise incomplete seal could allow untreated water to drip (or as I discovered, squirt) into the receiving vessel. When a part can be easily damaged and the damaging act is likely to occur, putting a warning tape on the part might well serve the interests of all concerned.
The directions are clear enough. I read 'em a half-dozen times to make sure I wouldn't do something wrong again.
I had a hard enough time at the kitchen sink. The fill hole (from removing only the little white cap) is too small. Even under the stream of a controlled outlet I couldn't keep from getting spill on the outside of the bottle; and of course any spill on the outside could drip into a receiving vessel. (So I do wonder about the website pic of the bottle being dunked in a stream to fill it.) Water doesn't freely flow in, it has to settle in while the foam absorbs it. The bottle easily overflows as it 'burps' air and can take a minute or so to fill. Holding the bottle up to look for the line (which my eagle eyes struggle to see) compresses the bottle, raising the water level, (which I also find not that easy to see). Setting it on the counter relaxes the bottle, lowering the water level.
The correctly-full bottle & filter weigh 35.6 oz (1,010 g). (If I'm using it as a trail bottle, the filter has to be attached.) Squeezing it perhaps akin to choking two rattle snakes together I managed to get the weight down to about 17 oz (480 gm). Do I want to carry over 2 lb (0.9 kg) of water bottle that has a little over a pound (0.45 kg) of accessible water in it? If I have to carry my regular trail bottle anyway, then the S1 bottle becomes 3/4 lb (350 g) additional (rather than alternative) baggage. (I can squeeze more water out with the filter off.)
Even for me it's difficult to put the Micro Squeeze filter on backwards, but with the blue adapter, not impossible. Some kind of direction indicator on the filter would be helpful, especially for backflushing. Clean end dirty end? It's raining. I'm cold. Mosquitoes are eating me. I'm lost and it's getting dark. Am I going to be able to figure this out? To be fair, if I can't, water pathogens may not be my biggest concern.
I'm no youngster, and squeezing out two rations made my knarly fingers hurt so much I couldn't twiddle my thumbs the rest of the day. Directions suggest being able to yield about 20-22 oz (0.6-0.65 L). I squeezed the bottle with all my measly might and couldn't quite manage the low end. Or in simpler terms, I find the S1 too hard to squeeze; even if only to perform the initial 10. I also noted on the white sink what appeared to be charcoal dust from backflushing the filter, which I assumed (incorrectly) to be loose charcoal coming from the filter, a not uncommon circumstance with new filters.
I need 4-5 L (qts) a day. With my trail partner we'll need a few more. When no fires allowed, that means 6-7 L (qts) or so per day a little better than 0.5 L (pint) at a time = something in the order of a dozen cycles. Can I do that--at all, in the first place? And without messing a drop of untreated water into the receiving vessel? I can't keep sink-drawn water off the bottle, I cannot imagine how such a feat will be accomplished teetering at the edge of a stream. The product is surely not intended for tandems, but even solo, I don't see it as an exclusive water system and toting more than one does not suit my backpacking style.
I'm unclear as to whether the usage-life claim refers to the filter, the bottle or the bottle's internal workings; or all of the above. Website says the Micro Squeeze filter (presumably the same one) is good for a buzzillion gallons; package says the system is good for 1,600 uses, which at say, the top end of 22 oz (0.65 L) each would be about 1,100 qts (1,000 L). That certainly is abundant. If use averages 3 qts (L) a day it would take about 350 days--five years at my current average--to use it up. I don't find any instruction or indication to know how to determine the system is exhausted; though in practical terms I'd regard using it up an unlikely prospect. As the Micro Squeeze filter can be purchased separately, presumably Sawyer's lesser calculation applies to the bottle and/or innards. I don't find any reference regarding a replacement bottle.
Somewhat confusing to me are the website descriptions of the S1 & S3 models appearing to remove all of the same pathogens; though a deeper plunge into the stats reveals a key difference. Evidently S1 does not (and S3 does) remove viruses and heavy metals. At my typical rate of comprehension I could not tell the difference. I suspect a copy editing oversight; though possibly something more in the area of aforementioned comprehension.
Directions indicate flushing the bottle should require only a half-full bottle one time, without the filter. After that and then two full bottle attempts and two filter backflushes; the Eureka moment finally struck that perhaps the stubbornness of the Micro Squeeze filter must be related to charcoal going into it and not from it. I flushed the bottle eight more times without the filter. Even then, the filter clogged up before it passed barely enough water to backflush it. This would of course render the system useless in the field.
It finally also sunk in to test the filter alone, at home, before relying on it in the woods. Backflushed and hooked up to a head-high bag, the filter's gravity flow rate is (at least for the test L/qt of tap water) satisfactory.
Using Sawyer's online customer service form I inquired as to whether the bottle innards might somehow be not working as intended as after 10 1/2 flushes it is still releasing easily visible amounts of charcoal. (Photo shows result of last 8 full-bottle flushes; does not include first 2 1/2. The powder recovered and dried amounted to half-a-teaspoon.) That contact was not successful, but the test monitor suggested persistence in fidelity to BGT test procedure. Directly sending an email established several timely exchanges ultimately resulting in a (vendor-paid shipping) return and replacement system.
SUMMATION: Not easy to fill; hard for me to squeeze; would be relatively heavy in use; clogged immediately.
a) No hanging
b) No pumping
c) No chemicals to add
d) 10 seconds waiting & squeezing to prepare for filtering
e) $ competitive system
f) Heavy when in use
g) Bulky to use
h) Too much squeezing
i) Not practical as a lone water system
j) "Grabby" surface on bottle
k) Not suitable to my style of backpacking
l) Clogged with charcoal.
1. Oct 13-18, 2021: Emigrant Wilderness, California. 5 nights, 14 mi (22 km) trail + 3 mi (5 km) XC; leave weight 43 lb (20 kg), return 37 lb (17 kg); 32-60 F (0-16 C); 6,000-8,000 ft (1,800-2,400 m); 4 camps. 2 days algae-stained water; 4 days clear water; 2 persons.
2. Nov 2-5, 2021: Emigrant Wilderness, California. 3 nights, 13 mi (21 km); leave weight 43 lb (20 kg), return 39 lb (18 kg); 32-50 F (0-10 C); 7,200-9,200 ft (2,200-2,800 m); 3 camps. Clear snow-melt; 1 person.
As a gravity filter the Micro Squeeze met two people's total hydration needs for six days. It did require backflushing once or twice a day; and doesn't go faster than a trickle even when freshly flushed. Of course the higher the source hangs, the faster the flow. I never had occasion to time it. It is certainly not speedy; though I have another similar type that is no faster; and also the previously referenced Sawyer product that is faster. Micro works fine in camp while I'm doing other chores. The time required to refill a trail bottle makes it not practical during a hike. (Perhaps worthy to note that the older Sawyer drip/inline filter while being faster and so far never having required field-flushing, does not remove algae stain.)
The Micro Squeeze removes algae stain, where source water is about the color of light tea. A spring where we normally get clear water was drought-tortured to a stagnant puddle laden with loose algae and copious debris. Straining through eight layers of paint screen removed all visible detritus except for the stain. Filtered water came out clear; and backflushed water started brown. The filter would handle about a 3-4 L/qts before dripping so slowly as to require backflushing. With clear water that was available at lake sources the filter would go about twice that before choking to an intolerably slow drip.
Of course I don't know what the unfiltered water would taste like. I didn't notice any taste or odor to the output; nor did my partner.
The wet filter weighs 60 g (2.1 oz). It's roughly the size of a more oblong chicken egg--very small for a water filter. Because of the backflushing frequency necessity, relying on the filter requires carrying the included plunger, adding 26 g (1 oz) in weight and roughly 1 1/2 times as much bulk. Contact pressure alone will not make a tight seal between plunger and filter, meaning the hand holding the two together gets wet. This would be a meaningless nit on those days I carp about being too hot, but at near freezing temps the drenching takes on a different aspect. A dedicated short length of tubing or switching out the output hose would resolve that, but either nudges the fiddle needle toward the red zone. Two squirts through the filter seem to reach the maximum flush--maybe even one would do it. After the first half-plunger I don't observe dirty water squirting out.
Small has many advantages; not the least of which is taking up minimal space in a pocket to keep the device from freezing. Website advises that freezing can harm the filter (so far as I know the case for almost all backpacking filters). CS replied the S1 bottle may freeze without damage. The bottle would have to thaw out before use, but at least it doesn't have to go in the sleeping bag on chilly nights. I will not be able to hike with the bottle in now sub-freezing Sierra temperatures as I won't have a way to keep it warm enough--big and 'grabby' to have flopping around under my jacket. I don't know how cold temperatures would have to be and/or exposure time to cause a freeze-up. I have been on hikes where my trail bottle froze up enough I couldn't get water from it.
My priority for water treatment is straining out protozoa and bacteria; namely crypto, giardia and E. coli. The vendor's claim of 0.1 microns for the Micro catches those bugs. Were I inclined toward squeeze bottles it should be possible to extricate the charcoal-gushing bottle innards.
On a 'warm' December trip I had hoped to try the bottle, but its replacement was still in the ether. One morning on a 9,200 ft (2,800 m) ridge top was icy-cold breeze and I huddled in the tent to pack up as I wolfed morning gruel. The snow-melt I had was clear, drawn from a small, slowly seeping puddle. Outside was too cold and windy to bother hanging the drip filter I had with me or to have campfire. My gullet simply will not tolerate chemical treatments. And I'd apparently rather risk bugs than exhaust an emergency ration of stove fuel to bring ice water to boil. As I engaged the risk of swilling wild water a benefit of the S1 system became more apparent--it should be pretty easy to use in a tent.
SUMMATION: Micro Squeeze filter is a tiny, light, effective means for clearing water--a great little drip filter entirely suited to my backpacking priorities.
c) Removes even algae stain
d) Not rapid
e) Requires frequent backflushing
REPLACEMENT S1 UNIT received 12/9/21
Bottle w/black & white caps before use: 7 5/8 oz (217 g)
Micro Squeeze filter before use: 1 5/8 oz (46 g)
Plunger: 7/8 oz (26 g)
Adapter: 1/8 oz (5 g)
Cap: 1/8 oz (5 g)
All of the above: 10 5/8 oz (301 g)
Full bottle w/cap: 2 lb 2 1/8 oz (969 g)
Bottle tightly squeezed out, no cap: 11 3/4 oz (333 g)
Replacement bottle arrived with the reducer (black) cap barely engaging the bottle's threads, contrary to instructions to keep the cap tight.
I took great care to ensure I was following directions, (causing a level of stress possibly affecting procedure); excepting this time the replacement filter was never asked to endure the bottle's potential excretion of charcoal. I undertook the process with optimism; and the first dispatch of water resulted in a barely visible release of charcoal. A second revealed a little more. To keep things comparable, I dumped the first two flushes on the deck plants and started with the third, continuing through a tenth. To my chagrin, the replacement bottle expelled a comparable accumulation of charcoal.
Is the replacement defective as well; or is neither and such expulsions of charcoal to be expected as normal? One would have to assume the former, as how would a product useless in the field make it past prototype testing? Regarding the latter, it was clear in the first test that the filter clogged almost immediately. User error? That possibility must necessarily be accounted in my case. But if that's it, then the system is too complex and/or too vulnerable to acts of what I would contend to be reasonably expected user behavior. I'm afraid my testing of the bottle--which I'm sorry to say will not make it to the field--is brought to an early conclusion. Two consecutive failures inspire insufficient confidence in the system's reliability. Other testers' results may or may not be similar and readers are encouraged to peruse those tests before forming opinions. (Some people have won the lottery twice, so perhaps my experience is an anomaly.)
Thank you Sawyer and BackpackGearTest.org for the opportunity to test this product. Long Term Report for the Micro Squeeze to follow in two months.
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