The CO₂ cylinder is the heart of any sparkling water maker. Without it, there’s no fizz. But how exactly does it work, how long does it last, and what do you need to know about refilling and safety? This guide covers everything.
What is a CO₂ Cylinder?
A CO₂ cylinder is a pressurised metal canister filled with carbon dioxide (CO₂) gas in liquid form. When the valve is opened, the liquid CO₂ vaporises and flows as gas into your sparkling water maker, where it dissolves into water to create carbonation.
The cylinders used in home sparkling water makers are small, portable, and designed for safe household use. They are completely different from industrial CO₂ cylinders used in welding or refrigeration.
Food-Grade vs Industrial CO₂
Not all CO₂ is the same. There are two main grades:
- Food-grade CO₂ — 99.9%+ pure, certified safe for direct contact with food and beverages. This is what Bubblitz uses.
- Industrial CO₂ — lower purity, may contain contaminants. Never use industrial CO₂ in a sparkling water maker.
Always ensure your CO₂ cylinder is labelled food-grade before using it for carbonation.
How Much CO₂ is in a Cylinder?
A standard Bubblitz CO₂ cylinder contains 400g–425g of food-grade CO₂. This is enough to make approximately 40–60 litres of sparkling water, depending on your carbonation level.
- Light carbonation — closer to 60 litres per cylinder
- Medium carbonation — approximately 50 litres per cylinder
- Heavy carbonation — closer to 40 litres per cylinder
How Does the Cylinder Connect to the Machine?
Screw-in (W21.8 thread) — the most common type. Used by Bubblitz Carbonator 1, 2, 3, 4, 5, SodaStream (screw-in models), Aarke, Drinkmate, Breville, and Philips.
Quick Connect — a push-and-click mechanism for faster cylinder changes. Bubblitz also offers a Quick Connect cylinder for these machines.
How Do I Know When the Cylinder is Empty?
- Your sparkling water is less fizzy than usual even after pressing the lever multiple times
- You hear less gas releasing when you press the carbonation button
- The cylinder feels noticeably lighter than when full
How Do CO₂ Refills Work?
- Order a CO₂ refill online
- Send your empty cylinder back to us
- Once we receive your empty, we dispatch a fresh filled cylinder
- Attach and carbonate as normal
No subscription required — just order when you need it.
CO₂ Cylinder Safety
- Store upright — always store cylinders in an upright position
- Avoid heat — keep away from direct sunlight and heat sources above 50°C
- Don’t puncture — never attempt to open, modify, or puncture a cylinder
- Food-grade only — only use food-grade CO₂ cylinders in your sparkling water maker
Frequently Asked Questions
Can I use a SodaStream cylinder in a Bubblitz machine?
Yes — if it uses a standard W21.8 screw-in thread, it is compatible with all Bubblitz Carbonators.
Can I refill my cylinder at home?
We do not recommend this. Use the Bubblitz cylinder swap service for safe, properly filled replacements.
Do I need a special adapter for a 5kg cylinder?
Yes — you need the 5kg CO₂ Hose & Adapter Kit.
Make Water Cool Again. 💧
