Grayl GeoPress Ti Purifier Review: Water Filtering ≠ Purifying – Hailey Moore | The Radavist | A group of individuals who share a love of cycling and the outdoors.

Water filtration does not equal water purification: there are different levels to the process of creating safe, clean drinking water. In a review of Grayl’s GeoPress titanium travel purifier, Hailey Moore explains what gets missed by filters alone and why you might consider carrying a purifying system.

For summer adventures in Colorado, I always carry a water filter. Numerous pocketable options exist today that stow easily for backcountry riding or alpine running and being able to refill mid-outing alleviates the burden of starting with excess water weight. And, for the most part, I’ve found filtering to be effective. The two times I’ve had giardia, however, are the exceptions to the rule where filtering—whether a result of the product itself, or user error—was disastrously ineffective. Since those two incidents, I’ve learned to be a little more mindful about the sources I’ll dip from. In general, the smaller and higher (elevation) the flow, the cleaner the water, though you still want to be aware of what’s upstream (Grazing cattle? Sprayed fields? Mine tailings?). But, at a recent outdoor industry event, I heard a few folks from the brand Grayl emphasizing that their solution to sourcing water in the backcountry is more than a filter, it’s a purifier, too. Having giardia isn’t something you soon forget and I was intrigued: was there something I was missing?

Filtering vs. Purifying

If, like me, you hadn’t previously given the filtration-versus-purification distinction much thought, the first step in understanding how to make water clean is knowing what makes it unclean. There are a few categories of contaminants that can be present in water. From largest to smallest in terms of size, these are: particulates (sediment and microplastics), pathogens (i.e. “bugs” including bacteria, protozoa, and viruses), chemicals (like chlorine, pesticides, PFAS, and VOCs), and heavy metals.

In very broad strokes, most filters can pick up the big stuff by essentially forcing water through a very intricate strainer. Picture: dumping a pot of penne through a colander. Being the largest contaminants, particulates like sediment and microplastics are weeded out. Of the pathogens, bacteria and protozoa (like my friend, giardiasis) are also large enough to get caught by a filter’s physical barrier. However, viruses are much smaller organisms and they, along with chemicals and heavy metals, are not eliminated from water by filtration alone.

Photos: Aaron LaVanchy

Purification takes removing contaminants to the next level. But instead of just going from a pasta-colander system to a fine-mesh strainer, purification often adds a bit more chemistry to the mix. Water purification can be achieved through several ways, or a combination thereof: ultraviolet (UV) treatment, reverse osmosis, electroadsorption (i.e. by leveraging the electric charge of ions), and other processes that I’d want a chemistry degree to talk about more in-depth. The catch is that the water still has to get through, too, ideally in an efficient manner if you’re trying to top off in a remote area. That’s where Grayl’s GeoPress Purifier comes in.

GeoPress® Ti Purifier: Quick(ish) Hits

Capacity: 24 oz (710 ml)
Weight: 20.125 oz (570 g); plastic version: 15.9 oz (450 g)
Height: 10.125″ (25.7 cm)
Materials: Titanium, BPA-FREE polypropylene #5, food-grade silicone, TPE and ABS food-grade plastic.
Active Technology: Electroadsorption and ultra-powdered activated carbon.
Fastest Flow Rate: 8 seconds per 24 oz (5 liters/minute)
Removes: waterborne pathogens (99.99% of viruses, 99.9999% of bacteria, 99.9% of protozoan cysts), including Rotavirus, Hepatitis A, Norovirus, Giardiasis, Cryptosporidium, E. Coli, Cholera, Salmonella, Dysentery and more.
Filters: particulates (i.e. silt, microplastics, etc.); ultra-powdered activated carbon effectively adsorbs chemicals (including PFAS & VOCs), pesticides, heavy metals, flavors, and odors.
Removable one-way drink-mix valve allows addition of electrolytes, etc., to the inner cup without back-clogging the cartridge.
Cartridge lifespan: rated for 350 cycles (65 gal. / 250L), as “press time” reaches ~25 seconds (or three years after first use) it’s time to replace your purifier cartridge. Unopened Purifier Cartridge has a 10-year shelf life.
Testing standards: independently tested by a certified laboratory to meet or exceed NSF/ANSI protocol 42 and 53 for pathogen and chemical removal; meets the United States Environmental Protection Agency’s Guide Standard and Protocol for testing microbiological water purifiers.
Origin: designed in USA; GeoPress® bottle components made in China (purifier cartridge media made in USA).
Patented
Price: $199.95 (titanium, 24 oz and 16.9 oz); $99.95 (plastic, 24 oz); $89.95 (plastic, 16.9 oz)

Grayl’s GeoPress Purifier, available in a titanium or hard plastic version, is a 24-ounce bottle that works as both a filter and a purifier. The ti version also doubles as a cookpot, but more on that later. (Grayl’s UltraPress employs the same technology in a smaller, 16.9-ounce package.)

The GeoPress’s design features two nesting cylindrical canisters, a filter/purifier cartridge, and a screw-top lid with a smaller, cap-covered drinking spout. On its own, the outer canister looks like a tall titanium cup, with folding butterfly handles, and it’s this piece that doubles as a cookpot. The inner canister holds the cartridge at its base and is sealed via the screw-top lid.

To use, fill the outer canister to the engraved fill line with dirty water then set it on a stable surface below waist height, ideally on the ground. Stack the inner canister and cartridge (which attaches to the bottom) unit on top of the outer canister. With the lid on, ensure that the cap is a half-turn open to act as an air escape valve. With palms placed on the ergonomic rubber pads on the lid, slowly press down. The combined forces of body weight and gravity create enough pressure to push the water from the outer canister up into the inner, clean chamber. Now your water is safe to drink.

All the dirty work of the GeoPress is happening in the canister and I spoke with Grayl co-founder Travis Merrigan about what exactly is going in that liminal space. He told me that Grayl’s purification technology starts with a foundation of non-woven ceramic filaments that work as a physical filter for those big bugs (bacteria, protozoa) and particulates (microplastics, sediment). The next stage is electroadsorption, where millions of tiny positively charged ions (think: tiny magnets) attract other, smaller unwanted contaminants that non-reactive physical barriers miss. See, some filters try to double-down on the physical-barrier model by making their pores smaller, but this can result in difficulties letting the water pass through and is also the reason that many filters rely on suction or squeezing. Lastly, the GeoPress cartridge includes powdered activated carbon—particles with the highest possible surface area—that further collect chemicals, metals, and viruses.

In-Use Impressions

Along with the added peace of mind that purifying water provides, I was most drawn to the GeoPress for its namesake (press) design. I often use a Katadyn BeFree filter flask or a Sawyer filter to re-fill bottles while riding and, I have to say, the squeezing can be tedious. When a filter is new, squeezing or drinking feels effortless. But, in my experience, a Kataydn filter cartridge (the replaceable mouth piece) only lasts about two years, with 85% of my usage being in the summer months, before working the water through the system starts to become a real chore. And, I don’t think I’m approaching anywhere near the 1000-liter life-span that’s advertised. Although certainly not as svelte, the press seemed like an interesting, upgraded alternative.

In use, I found the GeoPress to be fairly intuitive after watching a quick demo: the cartridge locks onto the inner canister with a half-turn; that unit then slides into the outer canister. Notably, the rubber-gasket seal between the cartridge and the inner canister works when there is no water present, i.e., when storing the GeoPress empty, I felt resistance when I had to press air through the cartridge (the same way that I would water) before the two canisters seated together.

The first few times I did press water through (as a trial at home), I noticed that removing the inner canister took some finesse, thanks again to this gasket. Grayl advises giving a slight twist while working the inner canister out before filling the outer with water; the keyword here is slight—and I’d add alternating left and right—otherwise you can unlock the cartridge from the inner canister and any pressed water will release back into the dirty, outer canister. After discovering the necessary technique, I didn’t have anymore trouble separating the two pieces.

I was impressed with the actual pressing process. Once stacked on top of the outer collection canister, it took about 8 seconds to slide the inner canister down and press all the water through. Grayl advertises that, when new, the GeoPress cartridge can move five liters per minute. I don’t think this takes into account having to remove and refill the outer canister, it’s just a metric for the cartridge itself. While this is faster than, for example, the Katadyn BeFree’s two liters per minute, what I appreciated more was how passive the GeoPress system felt. I expect the system to get slower with continued use—Grayl says that once the press time is 25 seconds it’s time to replace the cartridge—but during my test period, I barely had to exert any force. Gravity and a little patience does most of the work for you.

For bike-carry compatibility, the GeoPress is designed to pair with the Arundel Looney Bin adjustable cage. When facing out, the folding butterfly handles just clear the top of the cage. The 24 oz GeoPress does seem a bit tall for the Arundel cage (the 16.9 oz UltraPress would be a better fit), though so far it hasn’t jumped out. Still, since the cap requires stopping to unscrew before drinking, I’d probably opt to strap the GeoPress to a burlier cargo cage. Due to the D-ring component on the lid, I also found it easiest to carry on the fork legs.

For a product that already feels pretty spendy, the titanium version of the GeoPress adds a significant price jump up from the $99.95 plastic version to $199.95. As readers here are well aware, titanium is a premium material that adds durability while saving weight (as compared to stainless steel) and, in this case, allows the outer canister to serve as a cookpot. To me, the cylindrical design reads more “water boiler” than cookpot, but for backpackers that rely on dehydrated meals, this is basically the same thing, right? Conceptually, I am into the idea of the GeoPress Ti’s extended functionality.

In practice, I don’t think the shape really lends to much cooking outside of liquid meals because the targeted heat dispersal would require the most diligent stirring. It is also important to note that because the outer canister/cookpot is the half of the GeoPress used for collection, using it for cooking requires water to be boiled to avoid cross-contamination with any dregs of dirty water. Still, half the time I carry a JetBoil while touring (which is only about half the time), the main reason I bring it is to have hot instant coffee in the morning. From a volume perspective, packing the GeoPress Ti (on the frame) would eliminate my alternative combo of water filter and bulkier JetBoil that ride in my bike bags.

Lastly, the most significant design drawback that I see to the GeoPress is the rigidity of the system. Literally, the hard physical shell of the outer cup can make collecting from smaller sources—a shallow muddy puddle, or a barely-there mountain-side spring—pretty tricky. In the case of the latter example, I often deform the shape of the Katadyn’s flask to allow water to trickle in. Even if I can’t get the flask completely full, I’ll always take some water over no water. Perhaps the solution here is to carry a non-filter flask along with the GeoPress if this is a real concern, but this would add an extra step to the process.

Is it worth it?

This question is context dependent. As a US-based company, Grayl primarily positions their products to North American consumers—with North American gut microbiomes—with international travel and backpacking ambitions. The GeoPress may have been tweaked for cyclists, but it was not designed specifically for bike travel as is made readily evident by the screw cap. In our conversation, Travis Merrigan also made clear that purifiers’ additional benefit of removing viruses is not widely relevant in most of North America (though, he was quick to call out the slow-moving water and popular camping destination of the Grand Canyon as contributing to a US hotbed for virus-contaminated water). In the States, most of the time a filter is enough* if you are being selective with your water sources. There are always *caveats though: traveling through rangeland and/or mining terrain being top among them.

When I think about the best use cases for a water purification product like the GeoPress, I think about riders like Ryan Wilson and McKenzie Barney who have ridden the world over. That’s not to say that less frequent globe-trotters wouldn’t benefit from having a GeoPress at their disposal, either as a tool for touring or just for travel. When I visited Cape Town, South Africa, a couple years ago and did a shop visit with Mercer Bikes, I didn’t ride at all. After mistakenly drinking the tap water for the first 48 hours, I did however end up buying a lot of bottled water. If I’d had a GeoPress, I could have simply purified the hotel room’s tap. Closer to home though, I’d make a case for the GeoPress for anyone who lives near closed or active mines. During my circumnavigation of the Sawatch Mountains—and any time I ride in the Leadville area—I try to avoid filtering in the passes closest to town due to the area’s extensive mining history. I also think the GeoPress would make a great companion for trail crews who pack, or ride, gear into a worksite and spend the day or weekend in a relatively small area.

TL;DR

To me, the GeoPress Ti is a premium product with thoughtful design touches and capabilities that may sometimes extend the demands of my day-to-day riding. I know that I will continue to carry a more compact filter for shorter, day-use in familiar areas where I am more confident of the water’s quality. However, just like I bring an amped up repair and first-aid kit for extended backcountry missions, I think the GeoPress Ti is a smart tool for staying safe when venturing further afield, on the bike or otherwise. Due to the shorter expected lifespan of the filter cartridges (replaceable for $29.95) I would personally use the GeoPress selectively, prioritizing it for international travel and more remote touring, domestically or abroad. I appreciate that the outer canister can function as a serviceable cookpot for prepping a single-serving ramen or instant coffee, though this is a secondary benefit of the product.

Pros

Water purifiers outperform filters by also removing viruses, chemicals, and heavy metals from water.
Multi-purpose use as cookpot
Durable titanium construction