The Grayl Ultralight (UL) one press water purification and filtration system has been growing in popularity over the last few years due to its effectiveness and ease of use when safeguarding against microscopic impurities which fester in natural water sources. For a top down explanation, the operation of the Grayl UL is a simple one; fill, press, drink. And that is no simplification nor exaggeration, it really is that straightforward - think of its operation similar to a French coffee press.

The purification + filtration system is made up of four major parts; the outer bottle, the inner press bottle, the purifier cartridge and the locking screw cap. These four parts work smartly together to make water filtration easy and straightforward; what you do is fill the outer bottle up to the recommended line, place it on the ground (or a low flat surface) and then press the inner bottle (with the purifier cartridge attached) into the outer bottle and ‘through’ the water. It does a take a bit of muscle to press the inner bottle down hence why placing the outer bottle on the ground or a low flat surface allows you to use your entire body weight to make purification easier. It takes around 15-30 sec to complete the Grayl system operation and the water is ready to drink upon the completion of the press.  

So, when Grayl says fill, press, drink they do really mean, fill, press, drink.

The Grayl UL can handle the sorts of impurities found in chemically-flavoured tap water, bacteria-filled mountain streams, and virus-dwelling third world village wells. It is a high performing purifier + filter which has been designed to remove these major impurity groups which are commonly found in outdoor water sources.

So how does the Grayl stack up against these impurities?

Put simply, it stacks up extremely well.

The Grayl removes:              

+ 99.9999% of viruses (Rotavirus, Norovirus)

+ 99.9999% of bacteria (E.coli, Cholera)

+ 99.999% of protozoan cysts (Giardia, Cryptosporidium)

The Grayl filters out:                  

+ particulates (sediments, dirt)

+ many chemicals (chlorine, benzene)

+ heavy metals (lead, arsenic)

Where are these numbers coming from and what do they mean?

The numbers are from Grayl’s own website, and before you say, well of course they would promote such high numbers, I would recommend checking out their released lab reports - Click here to check them out.

The removal of impurities occurs within the purifier attached to the inner press bottle. The Purifier Cartridge houses a patented G3+™ Filtration Media which is fancy talk for ‘three filtration technologies combined into one.’ When you press the purifier down and through the outer bottle the water is forced to move through the purifier and the filtration media. As it does each filtration technology performs a different function to filter and purify impurities from the water.

The three filtration technologies are as follows:

+ An electro-adsorptive media which is a triple ion charged mesh. This creates a submicron trap (think of it as a magnet) for the trapping and removal of pathogens and inorganic compounds (bacteria, protozoan, viruses).

+ Ultra-powdered activated carbon which filters toxins and traps heavy metals and industrial chemicals.

+ Silver treated zeolites which is an anti-microbial agent which inhibits the growth of mould, mildew and bacteria to keep the purifier fresh between uses.

The G3+ Filtration Media maximises the effectiveness of filtering water as the one cartridge can filter out microscopic and particle impurities while keeping itself clean and free from microbes between uses. Just a note on filter length of use – each filter is estimated to last approx. 150 litres of filtered water (approx. 300 presses).

The Grayl UL not only provides quality water purification + filtration but offers all those other qualities and benefits which are important when it comes to using a water filter.

The Grayl UL can’t run out of batteries; it doesn’t taint the water with a nasty iodine taste; there is no hose to fight uncoiling; no bags to string up like a mad scientist; and there is no straw to go red faced sucking through. Plain and simple the Grayl is, well, plain and simple. But not in the plain jane sort of way, but that in minimal, highly considered and suitably functional sort of way. It is made from durable, thick plastic and holds up well against bangs, knocks and scratches. With each component feeling ‘chunky’ and tough (there are no flimsy, thin parts you must be delicate with) the bottle will blend into your other equipment and will handle the inherent ‘rough and tumble’ outdoor living comes with.

Even the simple process of operating the Grayl works in your favour – once the water has been filtered you are then left with a bottle of purified and filtered water which is as easy to drink as if one was drinking from a glass. This also makes it easy to refill your other water reserves, such as your camel pack or drink bottle, with clean, filtered water. The Grayl UL can also be easily shared around with others and the screw on lid enables the filtered water to be stored within the bottle. At only 309g the Grayl UL is relatively lightweight and the screw on lid facilitates a carabiner so the bottle can be clipped to your pack (or wherever is convenient). If there were any drawbacks to mention it would be the bottle capacity, which is slightly on the small size and requires regular filling and pressing if you are after large volumes of water. But this isn’t a major issue and falls to the wayside in comparison to the benefits and practicality of the using the Grayl UL. The Grayl UL offers water purification and filtration that is simple, portable and contained entirely within a bottle. It is the simplicity and effectiveness of the Grayl which makes it a fantastic piece of kit.  

It is a versatile water purifier/filter which transcends a range of outdoor activities. From the weekend adventurer to the multi-day mountain goat, the Grayl UL will be right at home clipped onto your pack.

The Grayl UL can be used not just as a safe option to provide clean, purified and filtered drinking water whilst outdoors, it can also be utilised to lighten your base weight. If you are a weight conscious adventurer who regularly heads out for day or overnight missions (hunting, fishing, tramping etc.) then the Grayl UL can be used as a smart way to lighten your load as it allows you to safely carry in less water*. For example, instead of carrying in 3L of water you can carry in 1.5L in your primary water reserve along with the Grayl UL – when you run out of your primary water supply you can safely and reassuringly fall back to your Grayl UL. Personally, I find this works great for overnighters, as when you are heading out the second day you are practically walking with an empty primary water reserve, which means a lighter pack, and you can just re-hydrate as you go with the Grayl UL from the river you are normally following back (plus having a bottle of water in the car isn’t a silly idea either).

*always prepare appropriately for the task you are undertaking, exercise common sense and carry in the appropriate amount of water that YOU require for the TYPE of environment and conditions you will be in.

If you are undertaking multi-day hunts/tramps or long distance tramps, e.g. the Te Aoroa Trail, then you will need to address safe water sourcing as no doubt your initial water supply will run out. This is where the Grayl UL is handy as it acts as a quick, on the go water provider and as a method of collecting larger volumes of clean, filtered water to resupply your primary water reserve. It also provides reassurance if things don’t go quite to plan as you have a method of collecting safe, drinkable water for the extra amount of unplanned days in the outdoors. With the number of incidents and accidents which occur in the outdoors, it is really a no-brainier when it comes to throwing the Grayl UL in your bag.

If you are frequently traveling and consider yourself a bit of an adventure traveller then the Grayl UL is again something which you will want to consider packing first. Whether it is a safari hunt in Africa, a long-distance trek through South America or an eye-opening explore through the urban towns of India, the Grayl UL has the purification and filtration power to keep at the bay those nasty viruses which are more commonly found in poorer water quality sources. There are plenty of Travel Blogs and travellers who use the Grayl UL and checking them out will give you a good idea of where the Grayl UL has been taken and used before.

The Grayl UL is also a very handy piece of survival gear in the case of an emergency. From the number of earthquakes, which have severally shaken parts of New Zealand over the last 7 years, it has been apparent water quality is one of the first resources to become compromised. Having a Grayl UL stored with your outdoor/ready-to-go gear is just another way to be prepared and to help yourself down the line when those situations arise.   

Overall the Grayl UL is versatile and this is what makes it so highly effective for a range of outdoor activities where safe water sourcing is an integral part to the whole experience. Obviously, the water purification/filtration market contains a range of options, each with their own advantages and draw backs (and course, if all else fails boiling water is tried and true) – but when measuring purification/ filtration performance and usability, the Grayl UL is a system which purifiers and filters water to an extremely high safety quality and this purification and filtration is achievable in a very easy-to-use and effective manner – minimising time, effort and risk in the outdoors.