The world's most in-depth and scientific reviews of outdoor gear

Grayl Ultralight Purifier Review

This water bottle purifies water borne pathogens including viruses and other contaminants.
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Price:  $60 List | $59.50 at Backcountry
Compare prices at 2 resellers
Pros:  Personal bottle, gets rid of viruses, durable, somewhat lightweight, useful for international travel
Cons:  Hard to press, limited storage capacity, short filter cartridge life
Manufacturer:   Grayl
By Amber King ⋅ Senior Review Editor  ⋅  May 6, 2019
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SCORE


RANKED
#18 of 20
  • Water Quality - 20% 10
  • Durability & Maintenance - 20% 5
  • Treatment Time - 15% 6
  • Weight & Packability - 15% 3
  • Ease of Set-Up - 15% 9
  • Ease of Filtration - 15% 3

Our Verdict

As a unique purification system, Grayl's Ultralight Bottle rids the most disgusting water sources of chemical contaminants as well as water-borne pathogens including viruses. For the most part, this purification system is terrific. It has applications for water sources all around the world. The body of the unit is incredibly durable, and water collection is super easy. Our most significant caveat is the actual filtration process. Similar to a french coffee press, you need to press the water through its filter, which takes some serious muscle, effort, and requires patience. Also…it can't filter out water with any turbidity; it literally can't be pushed down. Be sure you take water from clear sources or pre-filter before use.


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Overall Score Sort Icon
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Pros Personal bottle, gets rid of viruses, durable, somewhat lightweight, useful for international travelFast, easy, hands-free filtration, large volume, storageEasy to use, fast flow rate, collapsible, lightweightLightweight, adaptable, easy to use, lifetime guaranteeLightweight, great price, durable design, fast flow, high volume filtration
Cons Hard to press, limited storage capacity, short filter cartridge lifeA little expensive, can't gather from shallow sources, clogs with heavy sedimentLacks durability and reliabilityNot great for group use, better if you replace the bagsDoesn't filter out viruses, no additional storage reservoir
Bottom Line This water bottle purifies water borne pathogens including viruses and other contaminants.A fast and easy to use gravity filter perfect for dynamic duos, solo travelers, and groups.Our favorite lightweight on-the-go filtration system.Simple filtration that is light and reliable with a lifetime guarantee.The best value gravity filter on the market.
Rating Categories Grayl Ultralight Purifier Platypus GravityWorks Katadyn BeFree Sawyer Squeeze Katadyn Gravity Camp 6L
Water Quality (20%)
10
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10
10
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8
10
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8
10
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8
10
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8
Durability & Maintenance (20%)
10
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5
10
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6
10
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1
10
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5
10
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6
Treatment Time (15%)
10
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6
10
0
9
10
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10
10
0
9
10
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8
Weight & Packability (15%)
10
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3
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7
10
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10
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7
10
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6
Ease Of Set Up (15%)
10
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9
10
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7
10
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9
10
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7
10
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6
Ease Of Filtration (15%)
10
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3
10
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9
10
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9
10
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8
10
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9
Specs Grayl Ultralight... Platypus... Katadyn BeFree Sawyer Squeeze Katadyn Gravity...
Type of Filter Press action Gravity filter Squeeze & on-the-go Squeeze, in-line, on-the-go Gravity filter
Time to Treat One Liter (Timed Test) 40 seconds 52 seconds immediate 40 seconds 64 seconds
Measured Weight (entire kit -- oz) 11.5 oz 11.5 oz 2.1 oz 5.7 oz 11.7 oz
Storage Capacity ~500 mL 4L 0.6 L Varies 6L
Removes Bacteria? Yes Yes Yes Yes Yes
Removes Protozoa? (Cryptosporidium, Giardia Yes Yes Yes Yes Yes
Removes Viruses'? Yes No No No No
Removes Chemicals? Yes No No No No
Removes Heavy Metals? Yes No No No No
Removes Particulates (sediment, microplastics)? Yes Yes Yes Yes Yes
Filter Pore Size N/A 0.2 microns 0.1 micron 0.1 micron 0.2 microns
Advertised Flow Rate Varies 1.75L/min 2.11 liters per min 1.7L/min 2 L/min
Dimensions 9.6 x 2.9 in 9.4 x 3 in 9.05 in x 2.73 in 11 x 6 10 x 6 x 2.4 in
Filter Media or Active Ingredient Electro-absorption/Activated powdered carbon Hollow fiber Hollow Fiber Hollow Fiber Pleated glassfiber
# of liters/galloons per lifetime 151 liters/40 gallons 1,500 liters/396 gallons 1000 liters/264 gallons 378,541 liters/100,000 gallons 1,500 liters/396 gallons
Water Bottle Adapter Yes No Yes No No

Our Analysis and Test Results

Grayl also has the Geopress that seems to perform better overall. Here are their claimed differences of the Geopress vs. the Ultralight:
  • Better claimed filtration rate (8 seconds vs. 15 seconds per container)
  • Better filter cartridge longevity (250 liters vs. 150 liters)
  • Makes more water per press (24 ounces vs. 16 ounces)
  • It is heavier than the ultralight (weighs about 5 ounces more)

We've tested these differences, and while the numbers aren't exact, we do prefer the Geopress for most applications and it's one of our top scorers! Be sure to check out the review on this product.


Hands-On Review


The Grayl Ultralight is a lightweight water purification system perfect for international travel. It can transform disgusting murky water into a pristine delicious experience.

Performance Comparison


The Grayl Purifier is perfect for international travel as it filters out everything. Just be careful because it can't be pushed down with heavy amounts of sediment or silt.
The Grayl Purifier is perfect for international travel as it filters out everything. Just be careful because it can't be pushed down with heavy amounts of sediment or silt.

Water Quality


One of the best things about this purification system is water quality. The purification media utilizes a combination of activated carbon and ion exchange technology acts like tiny magnets to rid your water of pathogens that could make you sick while traveling internationally. The ion exchange technology does not use pore size and instead uses the charged properties of the proteins in the microorganisms, to suck them up, cleansing the water of bacteria, protozoa (Cryptosporidium and Giardia) and viruses. In addition to these pathogens, the powdered activated carbon clears the water of chemicals, pesticides, and heavy metals.

A look at the interior cylinder and the filtration unit that can get rid of viruses and other pathogens.
A look at the interior cylinder and the filtration unit that can get rid of viruses and other pathogens.

When doing taste tests, this filter actually made our tap water taste better and cleared out water from pretty disgusting water sources. The purification media also clears what of particulates and other stuff. Just don't trust that it'll work when the water looks like chocolate milk.

A look at the internal anatomy of the filtration cartridge that is loaded with ion exchange technology and powdered activated carbon.
A look at the internal anatomy of the filtration cartridge that is loaded with ion exchange technology and powdered activated carbon.

It's important to note that this filter does not work in super turbid water. We couldn't press any of the water through when it was muddy. It will only work in clear water. Be sure to prefilter is you find yourself in this type of environment.

Durability & Maintenance


This system is made from Polypropylene materials and seems fairly durable. We wouldn't expect it to survive if you accidentally tossed it over a cliff, but it survives basic ground drops (the biggest concern). Our only major concern is the gaskets wearing out over time or the lid accidentally breaking, which would render this unit useless. That said, we haven't read about any problems like this online nor have we experienced any issues after throwing it around for a few months.

While made out of plastic  the seals seem to be bomber while the plastic (with water inside) holds up to drop tests.
While made out of plastic, the seals seem to be bomber while the plastic (with water inside) holds up to drop tests.

We performed drop tests with the bottle completely full of water. We dropped it from knee level, chest level, and head level on a concrete surface. Each time we dropped it on the lid, bottom, side, and along seams that we thought might bust. In all cases, the unit stayed intact with just a few scrapes to show for it. As a result, we'd recommend it for the backcountry. The only issue is that if it does break, you need to have an emergency backup system ready.

Performing a drop test on a rock. Surprisingly it holds pretty well!
Performing a drop test on a rock. Surprisingly it holds pretty well!

The filter lasts for a measly 150L or 40 gallons. Most other filtrations systems last much longer than this. Currently, the replacement is about $25 which isn't too bad but doesn't have the longevity of other hollow filtration systems we've seen. The shorter lifespan is attributed to the unique virus removal technology.

All products by Grayl are covered under their 10-year warranty. Customer service is easy to work with and they are a small company. Quick to respond, attentive, and incredibly helpful. A good company to work with!

Treatment Time


Grayl does claim that this particular system can clean water at a rate of 15 seconds per 16 oz or 2 minutes per liter if you don't count the time to refill in between. We did three different tests in clear water, just at the kitchen sink at home. Prior to this, we followed all online advice to ensure that the system was set up correctly.

Over three timed trials, the average rate of flow was about 40 seconds per bottle (when following instructions closely), even new out of the box. When doing this again at the Colorado River, we had a heck of a time trying to filter as the particulates were blocking the chemical filter completely. We couldn't filter our water is this medium.

We timed trials to see how long it takes to filter the water. This takes longer than the company's claimed 15 seconds. If the water is turbid...good luck!
We timed trials to see how long it takes to filter the water. This takes longer than the company's claimed 15 seconds. If the water is turbid...good luck!

Weight & Packability


This unit weighs about 11.45 oz when completely empty. In comparison to a normal Nalgene bottle, it weighs more with the filter cartridge and the plastic material.


While it's in the same weight class as gravity filter kits, it's still relatively heavy when comparing other filtration options (with the exception of the MSR Guardian, purifying hand pump). The narrow profile does allow for this bottle to be packed away into a backpack, and the water-sealed lid guarantees that water won't leak in your bag.

While this is called an "ultralight" container  it is pretty heavy for a personal bottle system.
While this is called an "ultralight" container, it is pretty heavy for a personal bottle system.

Ease of Set-Up


Set-up is ridiculously easy. This unit has two cylindrical tubes that slid into one another. When we first got this out of the box, it was really hard to pull these tubes apart as the gaskets that create a seal is incredibly tight. Though on your first try, just twist each tube in the opposite direction and they will come apart.

Fill-up is pretty simple. Just dip and go!
Fill-up is pretty simple. Just dip and go!

From there, fill up your water canister. It's important that you note the "maximum" fill line. If you go above it, your water will spill out while purifying, risking possible contamination for the clean water that resides in the bottle. Once it's all filled, make sure the top is off as air needs to escape while you press one tube into another. Be sure to place the top in a safe place and don't put it near the water that is contaminated. This system does not purify water that can get caught on the threads of the top. Set it up on a flat or solid surface and get ready for the pressing of your life!!


Filling up this canister is problematic in super-duper shallow pools or in water sources that are out of arms reach. Steep banks on a riverside also pose a problem. Anywhere you can scoop water, you can use this purification system.

Ease of Filtration


This is where this unit loses some serious points. Despite all the online review videos that show the user pressing this bottle with ease, it is hard (or we're doing something wrong)!! The two canisters that fit inside of each other are completely sealed. The air that escapes is pressed down into the housing and escapes through the filtration cartridge.

It was soooo hard to press this thing down! We were able to do it pretty easily when water was clear. Here  we try with lots of turbidities. Unfortunately  we were unsuccessful...even after both of us gave it a shot.
It was soooo hard to press this thing down! We were able to do it pretty easily when water was clear. Here, we try with lots of turbidities. Unfortunately, we were unsuccessful...even after both of us gave it a shot.

To press it down, you need to position your hands at the rim of the interior cylinder and press all of your weight onto your hands, slowly pushing the air out which also forces the water through the cartridge at the bottom. This leaves clean water in the interior cartridge. At the end of each filtration, our hands were left sore with imprints from pressing down on the lid. If you didn't have a solid surface to do this on (like in a canoe), it'd be difficult to filter. Overall, filtration is difficult and not our favorite.

I gave it a shot  but couldn't get the dirty water through. This process is definitely NOT painless.
I gave it a shot, but couldn't get the dirty water through. This process is definitely NOT painless.

Value


The retail price includes the filter and the bottle press system. Given that the cartridge life isn't super long, it's not as high value as other options that will last an apparent lifetime without replacement. Value is decent but not the best overall.

Kasia enjoys a hike high up on a bluff in unknown lands. A great place for the Grayl Ultralight  while on a short hike  close to town where you might find a clear water source.
Kasia enjoys a hike high up on a bluff in unknown lands. A great place for the Grayl Ultralight, while on a short hike, close to town where you might find a clear water source.

Conclusion


The Grayl Ultralight is a convenient water purifier that can remove harmful waterborne pathogen including viruses. The activated charcoal makes water taste better by removing pesticides, heavy metals, and contaminants. It's not the most lightweight unit out there and the filtration is a bit painful and takes what seems forever (but is closer to 40 seconds).


Amber King