This guide is written by Echo Water, which makes the Echo Flask. Product facts come from Echo's own specifications and support guides and from an independent lab report, and we say which is which. The science links go to Hydrogen Studies, a research database that Echo Technologies also funds. It reports null results alongside positive ones.
Short answer: a hydrogen water bottle runs a small electric current through water. That splits some of the water into hydrogen gas and oxygen gas (electrolysis), and the hydrogen dissolves into the water you drink. In the Echo Flask, a proton exchange membrane (PEM, also called SPE) keeps the oxygen side apart from your drinking water and vents the oxygen out of the base. Meanwhile the sealed bottle builds pressure, which Echo puts at about 55 PSI on a 10-minute cycle and 77 PSI on a 20-minute cycle, so more hydrogen dissolves. In an independent lab test, the water held 6.07 mg/L of hydrogen after 10 minutes and 8.25 mg/L after 20. Once you open the cap, the hydrogen starts to escape, so drink it soon after each cycle.
What a hydrogen water bottle does, and what it doesn't
A hydrogen water bottle does one thing: it adds dissolved hydrogen gas (H₂) to ordinary water. The water is still H₂O. It isn't "H3O" or "H4O2" water, and it isn't alkaline water, which is defined by its pH rather than by a dissolved gas (here's a plain-language explainer on what hydrogen water is). Echo says the Flask keeps the water's pH neutral, adding no acidity or alkalinity.
What drinking that hydrogen does for you is a separate question that's still being studied; most of the research is in cells and animals, and the human trials are mostly small and short (see is hydrogen water real or fake?). This page explains the device.
What happens during an Echo Flask cycle
- Fill and seal. Fill the Flask with about 12 oz (354 mL) of water and screw the cap on firmly so it seals.
- Start a cycle. Press play on the touchscreen, or start it from the Echo Water app. The default cycle is 10 minutes, and you can add time in one-minute steps up to 20.
- Split the water. Current flows through the electrolysis cell in the base, whose electrode plates are platinum-coated titanium. Hydrogen forms at the negative electrode (the cathode), on the drinking-water side of the membrane. Oxygen forms at the positive electrode (the anode), on the other side.
- Vent the oxygen. The oxygen leaves through an exhaust port on the bottom of the Flask, near the serial number. Echo says small drips of water from this port are normal, so run the Flask on a surface that can get wet.
- Dissolve the hydrogen under pressure. Fine hydrogen bubbles rise through the water, and gas collects in the sealed bottle, raising the pressure. A pressure-release valve in the lid lets off any excess, which is the hiss you sometimes hear.
- Release, open and drink. When the screen reads "Ready," press the release button on the cap, open it and drink.
Echo's support guides add that a new Flask can take up to a week of regular use to build full pressure and consistent bubbles, and that the membrane works best kept damp.
Why the membrane matters (PEM/SPE)
Electrolysis always makes two gases. In a bottle without a membrane, both electrodes sit in your drinking water. If that water contains chloride, as most tap water does, chlorine compounds can form at the oxygen-producing electrode (see how hydrogen water is made).
A PEM cell puts a thin solid polymer membrane between the two electrodes, which is why it's also sold as SPE (solid polymer electrolyte). The membrane carries hydrogen ions (protons) across so the reaction can run, while keeping the two sides apart. Hydrogen is released on your side; oxygen is released on the far side and vented. Echo describes the Flask's cell as a dual-chamber membrane design whose electrode plates don't touch the drinking water, and says it produces no chlorine, ozone or hydroxyl byproducts.
One caveat for every brand, including ours: Hydrogen Studies found no peer-reviewed human studies comparing electrolysis designs in consumer devices (see hydrogen water side effects), so a lab test of the water is stronger evidence.
Why pressure matters
At normal air pressure and room temperature, water holds only about 1.6 mg of hydrogen per liter (1.6 ppm). Getting more in takes pressure, the same reason a sealed soda stays fizzy. In lab tests, sealed pressure-resistant bottles held roughly 7–10 ppm (details in hydrogen water ppm levels).
The Flask uses the hydrogen it makes to pressurize itself. According to Echo, it reaches about 55 PSI on a 10-minute cycle and about 77 PSI on a 20-minute cycle. Air pressure at sea level is about 14.7 PSI, so that's several times normal. It's also why the inner bottle is made of a plastic called PPSU rather than glass; Echo says glass starts to crack at around 30–40 PSI.
10-minute vs 20-minute cycles: what the lab measured
H2 Analytics, a hydrogen-water testing lab, measured the Flask's output in January 2025 (report H2AR-250116-1, commissioned by Echo). It used distilled water at about 24.5 °C and ran each cycle three times. After each run it released the pressure, removed the cap and immediately drew a sample for gas chromatography (static headspace analysis).
| Cycle | Pressure (Echo's figure) | Dissolved hydrogen (lab mean of 3 runs) | Hydrogen in a full bottle (about 350 mL) |
|---|---|---|---|
| 10 minutes | About 55 PSI | 6.07 mg/L | About 2.2 mg |
| 20 minutes | About 77 PSI | 8.25 mg/L | About 2.9 mg |
Read the full H2 Analytics report (PDF). Keep three things in mind:
- These were favorable conditions: distilled water, sampled the moment the cap came off.
- The ppm figure on the Flask's screen is an estimate based on cycle length, not a live reading. Echo says the Flask has no built-in hydrogen sensor.
- A higher number describes what's in the water, not what it does for you. Human trials have used roughly 0.5 to 15 ppm, and none has identified a best concentration (see how much hydrogen water per day).
A full charge gives about 60 minutes of generating time, or roughly 5–7 ten-minute cycles, according to Echo. You can run a second cycle before drinking, but release the pressure between cycles. Echo hasn't published test results for back-to-back cycles.
Why the hydrogen level falls after you open it
Water holding more than about 1.6 ppm is supersaturated: the extra hydrogen stays in only while pressure holds it there. Once you open the cap, hydrogen starts escaping, and pouring, shaking and warmth speed that up. In one trial, water measured 5.4 mg/L when it was made and 4.2 mg/L an hour after opening. Hydrogen also passes slowly through plastic and glass walls, while aluminum and stainless steel hold it much better (see ppm levels).
The practical rule is simple: drink it within a few minutes of opening, and run a fresh cycle rather than saving water that has sat open for hours.
How to test your Flask at home
- Use a hydrogen-specific method: redox-titration reagent drops made for dissolved hydrogen, or a dedicated dissolved-hydrogen meter.
- Don't use an ORP meter or pH strips. ORP responds to pH and other factors, so it can't tell you how much hydrogen is in the water.
- Don't judge by bubbles. Echo notes that bubble size and number change with water temperature, mineral content and altitude, and aren't a measure of concentration.
- Test right after releasing the pressure, then again after the time you'd usually take to finish the bottle.
- Test the water you normally drink. The lab used distilled water, and filtered or tap water may give a different result.
- Repeat a few times and average the readings.
You can do this within Echo's 60-day return window. Our Echo reviews and lab tests page collects the published reports in one place.
Keeping the Flask working well
Mineral scale builds up on electrolysis plates, especially with hard water. Echo recommends filtered, RO or distilled water, hand-washing only (never submerge it or use a dishwasher), the built-in Clean cycle, and vinegar descaling: monthly with RO or distilled water, twice a month with filtered water, and weekly with tap, spring or well water. Full steps are in Echo's Flask cleaning guide.
Frequently asked questions
How does a hydrogen water bottle work?
It uses electrolysis. A small electric current splits water into hydrogen and oxygen gas, and the hydrogen dissolves into the water you drink. Membrane (PEM/SPE) designs keep the oxygen side apart and vent it, and sealed bottles use pressure to dissolve more hydrogen than water holds at normal pressure.
Do hydrogen water bottles really work?
A well-made one really does put hydrogen into water, and you can check that with a lab report or reagent drops. Whether drinking it does more for you than plain water is unsettled, because the human trials are mostly small and short. See is hydrogen water real or fake?
What does a hydrogen water bottle do to the water?
It adds dissolved hydrogen gas. It doesn't change the water molecule, and a membrane design like the Flask's isn't meant to change the pH. The added hydrogen leaves the water over time once the bottle is opened.
Why does my Flask hiss, drip or sound different each time?
According to Echo, hissing usually means the lid valve is releasing extra pressure, small drips from the oxygen port on the bottom are normal, and sounds and bubbles vary with water temperature, minerals and how damp the membrane is. If the lid won't hold pressure or the Flask leaks steadily, contact Echo support. The Flask has a 5-year limited warranty.
Should I use a 10- or 20-minute cycle?
The 20-minute cycle put more hydrogen in the water in lab testing (8.25 vs 6.07 mg/L), but it uses twice the battery. No study has shown that the higher concentration does more for you, so pick the cycle that fits how and when you'll drink.
Compare before you buy
Our hydrogen water bottle buyer's guide lists nine things to check in any bottle, including ours, and bottle vs tablets vs cans compares formats. See Echo's portable hydrogen water collection, or the Echo Flask page for current pricing.
The evidence behind this guide
- What is hydrogen water?
- Hydrogen water ppm levels
- How much hydrogen water per day
- Hydrogen water side effects
- Is hydrogen water real or fake?
Written by Echo Water. Last reviewed September 24, 2026. This is general information, not medical advice.
