What Is a 60L CO2 Cylinder and How Does It Work?

The cylinder stays sealed until the machine’s valve opens and releases CO2 into cold water, where the gas dissolves under pressure. The “60L” label describes output, not tank size. Three details trip people up: what fits your machine, how much gas is inside, and where the safety limits sit.

How Does a 60L CO2 Cylinder Actually Carbonate Water?

Carbonation happens when compressed CO2 dissolves into cold water under pressure:

1. The cylinder screws or clicks into the soda maker’s valve assembly.
2. Pressing the button releases a measured burst of CO2.
3. The gas enters the sealed bottle and dissolves under pressure.
4. Releasing the button vents excess gas; the bottle seals in the dissolved CO2.

Cold water holds dissolved CO2 far better than warm water, which is why manufacturers tell you to chill it first. The cylinder is passive — no pump, battery, or electronics. All the work happens in the machine’s valve and the bottle’s seal.

What Is Inside a 60L Cylinder?

That fill weight, not the “60L” figure, tells you how much gas you’re buying. Spec sheets list working pressure around 150 bar and test pressure near 250 bar. Real-world output runs lower if you like heavy carbonation, since each press uses more gas.

Screw-In vs Quick Connect: Why Cylinders Aren’t Universal

A 60L cylinder only fits the connector type it was built for, and screw-in and Quick Connect cylinders are not interchangeable. Screw-in cylinders use a threaded neck — the M18 x P1.5, TR21-4 standard — that twists into older-style soda makers. Quick Connect cylinders use a push-in fitting and are often color-coded; one SodaStream Quick Connect model is sold as a pink cylinder so users can tell the systems apart. A screw-in listing states plainly that it works with SodaStream and other home soda makers but not with Quick Connect machines. Check your machine’s connector before ordering. If you’re comparing refill options, our tested roundup of 60L CO2 cylinders breaks down the picks by machine type and value.

One purchase note: the foil seal keeps the gas in. Once punctured on first use, that cylinder is committed to the machine it fits.

Pressure Safety and Refill Rules

Any regulator or connected equipment must be rated for at least the cylinder’s fill or maximum delivery pressure, because under-rated fittings can fail catastrophically. That guidance applies directly to home soda makers. Regulators should meet an approved standard, such as BS EN ISO 2503:2009 or equivalent, and match the gas used. Never jury-rig a cylinder into a machine it wasn’t designed for, and never store one where it can bake in direct sun or heat.

Refills are handled through exchange programs: you trade the empty cylinder for a full one, and the supplier inspects and refills to spec. Self-refilling, or buying from a seller who can’t show a food-grade CO2 source, saves a few dollars and gambles with your equipment. When a cylinder empties, carbonation weakens over several bottles, then stops entirely.