Our take This all-in-one Grayl filter catches bugs, off flavors, and everything else, leaving behind a cup full of the best-tasting water we had all year.
The system works kind of like a French press coffee filter. Fill the larger container to the line with dirty water, place the smaller container inside, and lean into it for about 15 seconds. Testers noted the watertight lid (which prevents cross contamination) has to be slightly ajar, or else it’s impossible to press down the filter. Ding: The heels of our hands got sore from pushing against the plastic rim.
The inner container holds just 16 ounces. It takes multiple fill-and-press cycles to top up Nalgenes or reservoirs, making this most appropriate for trips in places with lots of water where you can fill, press, cap, and move on.
Trail cred The three-tier filter is made from electroadsorptive media (a positively charged mesh that traps protozoa, bacteria, viruses, and chemicals), plus carbon for removing taste and heavy metals, and silver to keep the filter clean. “I drank water in Nepal out of this bottle for a month and never got sick,” said a pro snowboarder after a trek to Annapurna Base Camp. Drawback: The filter has to be replaced every 150 or so liters and new inserts cost $25.
The food-grade plastic is totally bombproof. “I dropped mine square on a rock when it was full and was expecting the worst,” says one Colorado tester, “but the bottle only took a superficial scratch.”